diff --git a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/AwsCustomizableOperationDecorator.kt b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/AwsCustomizableOperationDecorator.kt
deleted file mode 100644
index 878c4a851f..0000000000
--- a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/AwsCustomizableOperationDecorator.kt
+++ /dev/null
@@ -1,134 +0,0 @@
-/*
- * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
- * SPDX-License-Identifier: Apache-2.0
- */
-
-package software.amazon.smithy.rustsdk
-
-import software.amazon.smithy.rust.codegen.client.smithy.ClientRustModule
-import software.amazon.smithy.rust.codegen.client.smithy.generators.client.CustomizableOperationCustomization
-import software.amazon.smithy.rust.codegen.client.smithy.generators.client.CustomizableOperationSection
-import software.amazon.smithy.rust.codegen.core.rustlang.CargoDependency
-import software.amazon.smithy.rust.codegen.core.rustlang.Writable
-import software.amazon.smithy.rust.codegen.core.rustlang.rustTemplate
-import software.amazon.smithy.rust.codegen.core.rustlang.writable
-import software.amazon.smithy.rust.codegen.core.smithy.RuntimeConfig
-import software.amazon.smithy.rust.codegen.core.smithy.RuntimeType
-
-class CustomizableOperationTestHelpers(runtimeConfig: RuntimeConfig) :
-    CustomizableOperationCustomization() {
-    private val codegenScope = arrayOf(
-        *RuntimeType.preludeScope,
-        "AwsUserAgent" to AwsRuntimeType.awsHttp(runtimeConfig).resolve("user_agent::AwsUserAgent"),
-        "BeforeTransmitInterceptorContextMut" to RuntimeType.beforeTransmitInterceptorContextMut(runtimeConfig),
-        "ConfigBag" to RuntimeType.configBag(runtimeConfig),
-        "http" to CargoDependency.Http.toType(),
-        "InterceptorContext" to RuntimeType.interceptorContext(runtimeConfig),
-        "RuntimeComponentsBuilder" to RuntimeType.runtimeComponentsBuilder(runtimeConfig),
-        "SharedInterceptor" to RuntimeType.smithyRuntimeApi(runtimeConfig).resolve("client::interceptors::SharedInterceptor"),
-        "StaticRuntimePlugin" to RuntimeType.smithyRuntimeApi(runtimeConfig).resolve("client::runtime_plugin::StaticRuntimePlugin"),
-        "StaticTimeSource" to CargoDependency.smithyAsync(runtimeConfig).toType().resolve("time::StaticTimeSource"),
-        "TestParamsSetterInterceptor" to testParamsSetterInterceptor(),
-    )
-
-    // TODO(enableNewSmithyRuntimeCleanup): Delete this once test helpers on `CustomizableOperation` have been removed
-    private fun testParamsSetterInterceptor(): RuntimeType = RuntimeType.forInlineFun("TestParamsSetterInterceptor", ClientRustModule.Client.customize) {
-        rustTemplate(
-            """
-            mod test_params_setter_interceptor {
-                use aws_smithy_runtime_api::box_error::BoxError;
-                use aws_smithy_runtime_api::client::interceptors::context::BeforeTransmitInterceptorContextMut;
-                use aws_smithy_runtime_api::client::interceptors::Interceptor;
-                use aws_smithy_runtime_api::client::runtime_components::RuntimeComponents;
-                use aws_smithy_types::config_bag::ConfigBag;
-                use std::fmt;
-
-                pub(super) struct TestParamsSetterInterceptor<F> { f: F }
-
-                impl<F> fmt::Debug for TestParamsSetterInterceptor<F> {
-                    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-                        write!(f, "TestParamsSetterInterceptor")
-                    }
-                }
-
-                impl<F> TestParamsSetterInterceptor<F> {
-                    pub fn new(f: F) -> Self { Self { f } }
-                }
-
-                impl<F> Interceptor for TestParamsSetterInterceptor<F>
-                where
-                    F: Fn(&mut BeforeTransmitInterceptorContextMut<'_>, &mut ConfigBag) + Send + Sync + 'static,
-                {
-                    fn name(&self) -> &'static str {
-                        "TestParamsSetterInterceptor"
-                    }
-
-                    fn modify_before_signing(
-                        &self,
-                        context: &mut BeforeTransmitInterceptorContextMut<'_>,
-                        _runtime_components: &RuntimeComponents,
-                        cfg: &mut ConfigBag,
-                    ) -> Result<(), BoxError> {
-                        (self.f)(context, cfg);
-                        Ok(())
-                    }
-                }
-            }
-            use test_params_setter_interceptor::TestParamsSetterInterceptor;
-            """,
-            *codegenScope,
-        )
-    }
-
-    override fun section(section: CustomizableOperationSection): Writable =
-        writable {
-            if (section is CustomizableOperationSection.CustomizableOperationImpl) {
-                // TODO(enableNewSmithyRuntimeCleanup): Delete these utilities
-                rustTemplate(
-                    """
-                    ##[doc(hidden)]
-                    // This is a temporary method for testing. NEVER use it in production
-                    pub fn request_time_for_tests(self, request_time: ::std::time::SystemTime) -> Self {
-                        self.runtime_plugin(
-                            #{StaticRuntimePlugin}::new()
-                                .with_runtime_components(
-                                    #{RuntimeComponentsBuilder}::new("request_time_for_tests")
-                                        .with_time_source(Some(#{StaticTimeSource}::new(request_time)))
-                                )
-                        )
-                    }
-
-                    ##[doc(hidden)]
-                    // This is a temporary method for testing. NEVER use it in production
-                    pub fn user_agent_for_tests(mut self) -> Self {
-                        let interceptor = #{TestParamsSetterInterceptor}::new(|context: &mut #{BeforeTransmitInterceptorContextMut}<'_>, _: &mut #{ConfigBag}| {
-                            let headers = context.request_mut().headers_mut();
-                            let user_agent = #{AwsUserAgent}::for_tests();
-                            headers.insert(
-                                #{http}::header::USER_AGENT,
-                                #{http}::HeaderValue::try_from(user_agent.ua_header()).unwrap(),
-                            );
-                            headers.insert(
-                                #{http}::HeaderName::from_static("x-amz-user-agent"),
-                                #{http}::HeaderValue::try_from(user_agent.aws_ua_header()).unwrap(),
-                            );
-                        });
-                        self.interceptors.push(#{SharedInterceptor}::new(interceptor));
-                        self
-                    }
-
-                    ##[doc(hidden)]
-                    // This is a temporary method for testing. NEVER use it in production
-                    pub fn remove_invocation_id_for_tests(mut self) -> Self {
-                        let interceptor = #{TestParamsSetterInterceptor}::new(|context: &mut #{BeforeTransmitInterceptorContextMut}<'_>, _: &mut #{ConfigBag}| {
-                            context.request_mut().headers_mut().remove("amz-sdk-invocation-id");
-                        });
-                        self.interceptors.push(#{SharedInterceptor}::new(interceptor));
-                        self
-                    }
-                    """,
-                    *codegenScope,
-                )
-            }
-        }
-}
diff --git a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/AwsFluentClientDecorator.kt b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/AwsFluentClientDecorator.kt
index 3a1e6e6fbe..93fb926ffe 100644
--- a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/AwsFluentClientDecorator.kt
+++ b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/AwsFluentClientDecorator.kt
@@ -54,7 +54,7 @@ class AwsFluentClientDecorator : ClientCodegenDecorator {
                 AwsPresignedFluentBuilderMethod(codegenContext),
                 AwsFluentClientDocs(codegenContext),
             ),
-        ).render(rustCrate, listOf(CustomizableOperationTestHelpers(runtimeConfig)))
+        ).render(rustCrate, emptyList())
         rustCrate.withModule(ClientRustModule.client) {
             AwsFluentClientExtensions(codegenContext, types).render(this)
         }
diff --git a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/UserAgentDecorator.kt b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/UserAgentDecorator.kt
index 5d1ee8cb91..2619b224fc 100644
--- a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/UserAgentDecorator.kt
+++ b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/UserAgentDecorator.kt
@@ -105,6 +105,7 @@ class UserAgentDecorator : ClientCodegenDecorator {
         private val codegenScope = arrayOf(
             *preludeScope,
             "AppName" to AwsRuntimeType.awsTypes(runtimeConfig).resolve("app_name::AppName"),
+            "AwsUserAgent" to AwsRuntimeType.awsHttp(runtimeConfig).resolve("user_agent::AwsUserAgent"),
         )
 
         override fun section(section: ServiceConfig): Writable =
@@ -158,6 +159,15 @@ class UserAgentDecorator : ClientCodegenDecorator {
                     )
                 }
 
+                is ServiceConfig.DefaultForTests -> writable {
+                    rustTemplate(
+                        """
+                        self.config.store_put(#{AwsUserAgent}::for_tests());
+                        """,
+                        *codegenScope,
+                    )
+                }
+
                 else -> emptySection
             }
     }
diff --git a/aws/sdk/integration-tests/kms/Cargo.toml b/aws/sdk/integration-tests/kms/Cargo.toml
index a26e2dd672..0e84f1a0ec 100644
--- a/aws/sdk/integration-tests/kms/Cargo.toml
+++ b/aws/sdk/integration-tests/kms/Cargo.toml
@@ -10,11 +10,15 @@ publish = false
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[features]
+default = ["test-util"]
+test-util = []
+
 [dev-dependencies]
 aws-credential-types = { path = "../../build/aws-sdk/sdk/aws-credential-types", features = ["test-util"] }
 aws-http = { path = "../../build/aws-sdk/sdk/aws-http" }
 aws-runtime = { path = "../../build/aws-sdk/sdk/aws-runtime" }
-aws-sdk-kms = { path = "../../build/aws-sdk/sdk/kms" }
+aws-sdk-kms = { path = "../../build/aws-sdk/sdk/kms", features = ["test-util"] }
 aws-smithy-async = { path = "../../build/aws-sdk/sdk/aws-smithy-async", features = ["test-util"] }
 aws-smithy-http = { path = "../../build/aws-sdk/sdk/aws-smithy-http" }
 aws-smithy-types = { path = "../../build/aws-sdk/sdk/aws-smithy-types" }
diff --git a/aws/sdk/integration-tests/kms/tests/integration.rs b/aws/sdk/integration-tests/kms/tests/integration.rs
index e02e32ab52..96c862c0e6 100644
--- a/aws/sdk/integration-tests/kms/tests/integration.rs
+++ b/aws/sdk/integration-tests/kms/tests/integration.rs
@@ -11,7 +11,6 @@ use aws_smithy_runtime::client::http::test_util::{ReplayEvent, StaticReplayClien
 use http::header::AUTHORIZATION;
 use http::Uri;
 use kms::config::{Config, Credentials, Region};
-use std::time::{Duration, UNIX_EPOCH};
 
 // TODO(DVR): having the full HTTP requests right in the code is a bit gross, consider something
 // like https://github.com/davidbarsky/sigv4/blob/master/aws-sigv4/src/lib.rs#L283-L315 to store
@@ -45,6 +44,7 @@ async fn generate_random_cn() {
     http_client.assert_requests_match(&[]);
 }
 
+#[cfg(feature = "test-util")]
 #[tokio::test]
 async fn generate_random() {
     let http_client = StaticReplayClient::new(vec![ReplayEvent::new(
@@ -52,9 +52,8 @@ async fn generate_random() {
             .header("content-type", "application/x-amz-json-1.1")
             .header("x-amz-target", "TrentService.GenerateRandom")
             .header("content-length", "20")
-            .header("authorization", "AWS4-HMAC-SHA256 Credential=ANOTREAL/20210305/us-east-1/kms/aws4_request, SignedHeaders=content-length;content-type;host;x-amz-date;x-amz-security-token;x-amz-target;x-amz-user-agent, Signature=2e0dd7259fba92523d553173c452eba8a6ee7990fb5b1f8e2eccdeb75309e9e1")
-            .header("x-amz-date", "20210305T134922Z")
-            .header("x-amz-security-token", "notarealsessiontoken")
+            .header("authorization", "AWS4-HMAC-SHA256 Credential=ANOTREAL/20090213/us-east-1/kms/aws4_request, SignedHeaders=content-length;content-type;host;x-amz-date;x-amz-target;x-amz-user-agent, Signature=53dcf70f6f852cb576185dcabef5aaa3d068704cf1b7ea7dc644efeaa46674d7")
+            .header("x-amz-date", "20090213T233130Z")
             .header("user-agent", "aws-sdk-rust/0.123.test os/windows/XPSP3 lang/rust/1.50.0")
             .header("x-amz-user-agent", "aws-sdk-rust/0.123.test api/test-service/0.123 os/windows/XPSP3 lang/rust/1.50.0")
             .uri(Uri::from_static("https://kms.us-east-1.amazonaws.com/"))
@@ -67,6 +66,7 @@ async fn generate_random() {
         .http_client(http_client.clone())
         .region(Region::new("us-east-1"))
         .credentials_provider(Credentials::for_tests_with_session_token())
+        .with_test_defaults()
         .build();
     let client = kms::Client::from_conf(conf);
     let resp = client
@@ -77,8 +77,6 @@ async fn generate_random() {
             // Remove the invocation ID since the signed request above doesn't have it
             req.headers_mut().remove("amz-sdk-invocation-id");
         })
-        .request_time_for_tests(UNIX_EPOCH + Duration::from_secs(1614952162))
-        .user_agent_for_tests()
         .send()
         .await
         .expect("request should succeed");
@@ -118,6 +116,7 @@ async fn generate_random_malformed_response() {
         .expect_err("response was malformed");
 }
 
+#[cfg(feature = "test-util")]
 #[tokio::test]
 async fn generate_random_keystore_not_found() {
     let http_client = StaticReplayClient::new(vec![ReplayEvent::new(
@@ -125,9 +124,8 @@ async fn generate_random_keystore_not_found() {
             .header("content-type", "application/x-amz-json-1.1")
             .header("x-amz-target", "TrentService.GenerateRandom")
             .header("content-length", "56")
-            .header("authorization", "AWS4-HMAC-SHA256 Credential=ANOTREAL/20210305/us-east-1/kms/aws4_request, SignedHeaders=content-length;content-type;host;x-amz-target, Signature=4ca5cde61676c0ee49fde9ba3c886967e8af16461b6aafdfaee18033eb4ac7a5")
-            .header("x-amz-date", "20210305T144724Z")
-            .header("x-amz-security-token", "notarealsessiontoken")
+            .header("authorization", "AWS4-HMAC-SHA256 Credential=ANOTREAL/20090213/us-east-1/kms/aws4_request, SignedHeaders=content-length;content-type;host;x-amz-target, Signature=ffef92c6b75d66cc511daa896eb4a085ec053a2592e17d1f22ecaf167f2fa4bb")
+            .header("x-amz-date", "20090213T233130Z")
             .header("user-agent", "aws-sdk-rust/0.123.test os/windows/XPSP3 lang/rust/1.50.0")
             .header("x-amz-user-agent", "aws-sdk-rust/0.123.test api/test-service/0.123 os/windows/XPSP3 lang/rust/1.50.0")
             .uri(Uri::from_static("https://kms.us-east-1.amazonaws.com/"))
@@ -147,6 +145,7 @@ async fn generate_random_keystore_not_found() {
         .http_client(http_client.clone())
         .region(Region::new("us-east-1"))
         .credentials_provider(Credentials::for_tests_with_session_token())
+        .with_test_defaults()
         .build();
     let client = kms::Client::from_conf(conf);
 
@@ -154,9 +153,6 @@ async fn generate_random_keystore_not_found() {
         .generate_random()
         .number_of_bytes(64)
         .custom_key_store_id("does not exist")
-        .customize()
-        .request_time_for_tests(UNIX_EPOCH + Duration::from_secs(1614955644))
-        .user_agent_for_tests()
         .send()
         .await
         .expect_err("key store doesn't exist");
diff --git a/aws/sdk/integration-tests/qldbsession/Cargo.toml b/aws/sdk/integration-tests/qldbsession/Cargo.toml
index 59256fb6cd..fecc6e1495 100644
--- a/aws/sdk/integration-tests/qldbsession/Cargo.toml
+++ b/aws/sdk/integration-tests/qldbsession/Cargo.toml
@@ -10,10 +10,14 @@ publish = false
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[features]
+default = ["test-util"]
+test-util = []
+
 [dev-dependencies]
 aws-credential-types = { path = "../../build/aws-sdk/sdk/aws-credential-types", features = ["test-util"] }
 aws-http = { path = "../../build/aws-sdk/sdk/aws-http" }
-aws-sdk-qldbsession = { path = "../../build/aws-sdk/sdk/qldbsession" }
+aws-sdk-qldbsession = { path = "../../build/aws-sdk/sdk/qldbsession", features = ["test-util"] }
 aws-smithy-async = { path = "../../build/aws-sdk/sdk/aws-smithy-async" }
 aws-smithy-http = { path = "../../build/aws-sdk/sdk/aws-smithy-http" }
 aws-smithy-runtime = { path = "../../build/aws-sdk/sdk/aws-smithy-runtime", features = ["client", "test-util"] }
diff --git a/aws/sdk/integration-tests/qldbsession/tests/integration.rs b/aws/sdk/integration-tests/qldbsession/tests/integration.rs
index 18ba8e4999..0c167712d7 100644
--- a/aws/sdk/integration-tests/qldbsession/tests/integration.rs
+++ b/aws/sdk/integration-tests/qldbsession/tests/integration.rs
@@ -9,8 +9,8 @@ use aws_sdk_qldbsession::Client;
 use aws_smithy_http::body::SdkBody;
 use aws_smithy_runtime::client::http::test_util::{ReplayEvent, StaticReplayClient};
 use http::Uri;
-use std::time::{Duration, UNIX_EPOCH};
 
+#[cfg(feature = "test-util")]
 #[tokio::test]
 async fn signv4_use_correct_service_name() {
     let http_client = StaticReplayClient::new(vec![ReplayEvent::new(
@@ -18,10 +18,9 @@ async fn signv4_use_correct_service_name() {
             .header("content-type", "application/x-amz-json-1.0")
             .header("x-amz-target", "QLDBSession.SendCommand")
             .header("content-length", "49")
-            .header("authorization", "AWS4-HMAC-SHA256 Credential=ANOTREAL/20210305/us-east-1/qldb/aws4_request, SignedHeaders=content-length;content-type;host;x-amz-date;x-amz-security-token;x-amz-target;x-amz-user-agent, Signature=350f957e9b736ac3f636d16c59c0a3cee8c2780b0ffadc99bbca841b7f15bee4")
+            .header("authorization", "AWS4-HMAC-SHA256 Credential=ANOTREAL/20090213/us-east-1/qldb/aws4_request, SignedHeaders=content-length;content-type;host;x-amz-date;x-amz-target;x-amz-user-agent, Signature=9a07c60550504d015fb9a2b0f1b175a4d906651f9dd4ee44bebb32a802d03815")
             // qldbsession uses the signing name 'qldb' in signature _________________________^^^^
-            .header("x-amz-date", "20210305T134922Z")
-            .header("x-amz-security-token", "notarealsessiontoken")
+            .header("x-amz-date", "20090213T233130Z")
             .header("user-agent", "aws-sdk-rust/0.123.test os/windows/XPSP3 lang/rust/1.50.0")
             .uri(Uri::from_static("https://session.qldb.us-east-1.amazonaws.com/"))
             .body(SdkBody::from(r#"{"StartSession":{"LedgerName":"not-real-ledger"}}"#)).unwrap(),
@@ -33,6 +32,7 @@ async fn signv4_use_correct_service_name() {
         .http_client(http_client.clone())
         .region(Region::new("us-east-1"))
         .credentials_provider(Credentials::for_tests_with_session_token())
+        .with_test_defaults()
         .build();
     let client = Client::from_conf(conf);
 
@@ -45,9 +45,6 @@ async fn signv4_use_correct_service_name() {
                 .unwrap(),
         )
         .customize()
-        // Fix the request time and user agent so the headers are stable
-        .request_time_for_tests(UNIX_EPOCH + Duration::from_secs(1614952162))
-        .user_agent_for_tests()
         .mutate_request(|req| {
             // Remove the invocation ID since the signed request above doesn't have it
             req.headers_mut().remove("amz-sdk-invocation-id");
diff --git a/aws/sdk/integration-tests/s3/Cargo.toml b/aws/sdk/integration-tests/s3/Cargo.toml
index a525f69815..1cf92d5d21 100644
--- a/aws/sdk/integration-tests/s3/Cargo.toml
+++ b/aws/sdk/integration-tests/s3/Cargo.toml
@@ -10,13 +10,17 @@ publish = false
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[features]
+default = ["test-util"]
+test-util = []
+
 [dev-dependencies]
 async-std = "1.12.0"
 aws-config = { path = "../../build/aws-sdk/sdk/aws-config" }
 aws-credential-types = { path = "../../build/aws-sdk/sdk/aws-credential-types", features = ["test-util"] }
 aws-http = { path = "../../build/aws-sdk/sdk/aws-http" }
 aws-runtime = { path = "../../build/aws-sdk/sdk/aws-runtime", features = ["test-util"] }
-aws-sdk-s3 = { path = "../../build/aws-sdk/sdk/s3" }
+aws-sdk-s3 = { path = "../../build/aws-sdk/sdk/s3", features = ["test-util"] }
 aws-sdk-sts = { path = "../../build/aws-sdk/sdk/sts" }
 aws-smithy-async = { path = "../../build/aws-sdk/sdk/aws-smithy-async", features = ["test-util", "rt-tokio"] }
 aws-smithy-http = { path = "../../build/aws-sdk/sdk/aws-smithy-http" }
diff --git a/aws/sdk/integration-tests/s3/tests/checksums.rs b/aws/sdk/integration-tests/s3/tests/checksums.rs
index 79b8f92900..b6ea28fef5 100644
--- a/aws/sdk/integration-tests/s3/tests/checksums.rs
+++ b/aws/sdk/integration-tests/s3/tests/checksums.rs
@@ -7,8 +7,8 @@ use aws_config::SdkConfig;
 use aws_credential_types::provider::SharedCredentialsProvider;
 use aws_sdk_s3::config::{Credentials, Region};
 use aws_sdk_s3::types::ChecksumMode;
-use aws_sdk_s3::Client;
 use aws_sdk_s3::{operation::get_object::GetObjectOutput, types::ChecksumAlgorithm};
+use aws_sdk_s3::{Client, Config};
 use aws_smithy_http::body::SdkBody;
 use aws_smithy_runtime::client::http::test_util::{
     capture_request, ReplayEvent, StaticReplayClient,
@@ -25,30 +25,47 @@ fn new_checksum_validated_response_test_connection(
     checksum_header_name: &'static str,
     checksum_header_value: &'static str,
 ) -> StaticReplayClient {
-    StaticReplayClient::new(vec![
-        ReplayEvent::new(http::Request::builder()
-             .header("x-amz-checksum-mode", "ENABLED")
-             .header("user-agent", "aws-sdk-rust/0.123.test os/windows/XPSP3 lang/rust/1.50.0")
-             .header("x-amz-date", "20210618T170728Z")
-             .header("x-amz-content-sha256", "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855")
-             .header("x-amz-user-agent", "aws-sdk-rust/0.123.test api/test-service/0.123 os/windows/XPSP3 lang/rust/1.50.0")
-             .header("authorization", "AWS4-HMAC-SHA256 Credential=ANOTREAL/20210618/us-east-1/s3/aws4_request, SignedHeaders=host;x-amz-checksum-mode;x-amz-content-sha256;x-amz-date;x-amz-security-token;x-amz-user-agent, Signature=eb9e58fa4fb04c8e6f160705017fdbb497ccff0efee4227b3a56f900006c3882")
-             .uri(Uri::from_static("https://some-test-bucket.s3.us-east-1.amazonaws.com/test.txt?x-id=GetObject")).body(SdkBody::empty()).unwrap(),
-         http::Response::builder()
-             .header("x-amz-request-id", "4B4NGF0EAWN0GE63")
-             .header("content-length", "11")
-             .header("etag", "\"3e25960a79dbc69b674cd4ec67a72c62\"")
-             .header(checksum_header_name, checksum_header_value)
-             .header("content-type", "application/octet-stream")
-             .header("server", "AmazonS3")
-             .header("content-encoding", "")
-             .header("last-modified", "Tue, 21 Jun 2022 16:29:14 GMT")
-             .header("date", "Tue, 21 Jun 2022 16:29:23 GMT")
-             .header("x-amz-id-2", "kPl+IVVZAwsN8ePUyQJZ40WD9dzaqtr4eNESArqE68GSKtVvuvCTDe+SxhTT+JTUqXB1HL4OxNM=")
-             .header("accept-ranges", "bytes")
-             .status(http::StatusCode::from_u16(200).unwrap())
-             .body(SdkBody::from(r#"Hello world"#)).unwrap()),
-    ])
+    StaticReplayClient::new(vec![ReplayEvent::new(
+        http::Request::builder()
+            .header("x-amz-checksum-mode", "ENABLED")
+            .header(
+                "user-agent",
+                "aws-sdk-rust/0.123.test os/windows/XPSP3 lang/rust/1.50.0",
+            )
+            .header("x-amz-date", "20090213T233130Z")
+            .header(
+                "x-amz-content-sha256",
+                "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+            )
+            .header(
+                "x-amz-user-agent",
+                "aws-sdk-rust/0.123.test api/test-service/0.123 os/windows/XPSP3 lang/rust/1.50.0",
+            )
+            .header("authorization", "not-relevant")
+            .uri(Uri::from_static(
+                "https://some-test-bucket.s3.us-east-1.amazonaws.com/test.txt?x-id=GetObject",
+            ))
+            .body(SdkBody::empty())
+            .unwrap(),
+        http::Response::builder()
+            .header("x-amz-request-id", "4B4NGF0EAWN0GE63")
+            .header("content-length", "11")
+            .header("etag", "\"3e25960a79dbc69b674cd4ec67a72c62\"")
+            .header(checksum_header_name, checksum_header_value)
+            .header("content-type", "application/octet-stream")
+            .header("server", "AmazonS3")
+            .header("content-encoding", "")
+            .header("last-modified", "Tue, 21 Jun 2022 16:29:14 GMT")
+            .header("date", "Tue, 21 Jun 2022 16:29:23 GMT")
+            .header(
+                "x-amz-id-2",
+                "kPl+IVVZAwsN8ePUyQJZ40WD9dzaqtr4eNESArqE68GSKtVvuvCTDe+SxhTT+JTUqXB1HL4OxNM=",
+            )
+            .header("accept-ranges", "bytes")
+            .status(http::StatusCode::from_u16(200).unwrap())
+            .body(SdkBody::from(r#"Hello world"#))
+            .unwrap(),
+    )])
 }
 
 async fn test_checksum_on_streaming_response(
@@ -59,22 +76,20 @@ async fn test_checksum_on_streaming_response(
         checksum_header_name,
         checksum_header_value,
     );
-    let sdk_config = SdkConfig::builder()
+    let config = Config::builder()
         .credentials_provider(SharedCredentialsProvider::new(Credentials::for_tests()))
         .time_source(UNIX_EPOCH + Duration::from_secs(1624036048))
         .region(Region::new("us-east-1"))
         .http_client(http_client.clone())
+        .with_test_defaults()
         .build();
-
-    let client = Client::new(&sdk_config);
+    let client = Client::from_conf(config);
 
     let res = client
         .get_object()
         .bucket("some-test-bucket")
         .key("test.txt")
         .checksum_mode(aws_sdk_s3::types::ChecksumMode::Enabled)
-        .customize()
-        .user_agent_for_tests()
         .send()
         .await
         .unwrap();
@@ -150,13 +165,13 @@ async fn test_checksum_on_streaming_request<'a>(
     expected_aws_chunked_encoded_body: &'a str,
 ) {
     let (http_client, rcvr) = capture_request(None);
-    let sdk_config = SdkConfig::builder()
+    let config = Config::builder()
         .credentials_provider(SharedCredentialsProvider::new(Credentials::for_tests()))
         .region(Region::new("us-east-1"))
         .http_client(http_client.clone())
+        .with_test_defaults()
         .build();
-
-    let client = Client::new(&sdk_config);
+    let client = Client::from_conf(config);
 
     // ByteStreams created from a file are streaming and have a known size
     let mut file = tempfile::NamedTempFile::new().unwrap();
@@ -178,9 +193,6 @@ async fn test_checksum_on_streaming_request<'a>(
         .key("test.txt")
         .body(body)
         .checksum_algorithm(checksum_algorithm)
-        .customize()
-        .request_time_for_tests(UNIX_EPOCH + Duration::from_secs(1624036048))
-        .user_agent_for_tests()
         .send()
         .await
         .unwrap();
diff --git a/aws/sdk/integration-tests/s3/tests/config-override.rs b/aws/sdk/integration-tests/s3/tests/config-override.rs
index 76598b764c..5c1b08eee3 100644
--- a/aws/sdk/integration-tests/s3/tests/config-override.rs
+++ b/aws/sdk/integration-tests/s3/tests/config-override.rs
@@ -86,7 +86,6 @@ async fn operation_overrides_credentials_provider() {
             Some(std::time::UNIX_EPOCH + std::time::Duration::from_secs(1669257290 + 3600)),
             "test",
         )))
-        .request_time_for_tests(std::time::UNIX_EPOCH + std::time::Duration::from_secs(1669257290))
         .send()
         .await;
 
diff --git a/aws/sdk/integration-tests/s3/tests/customizable-operation.rs b/aws/sdk/integration-tests/s3/tests/customizable-operation.rs
index b7c7dfbf55..dd838e7efb 100644
--- a/aws/sdk/integration-tests/s3/tests/customizable-operation.rs
+++ b/aws/sdk/integration-tests/s3/tests/customizable-operation.rs
@@ -3,17 +3,16 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-use aws_config::SdkConfig;
 use aws_credential_types::provider::SharedCredentialsProvider;
 use aws_sdk_s3::config::{Credentials, Region};
-use aws_sdk_s3::Client;
+use aws_sdk_s3::{Client, Config};
 use aws_smithy_runtime::client::http::test_util::capture_request;
-use std::time::{Duration, UNIX_EPOCH};
+use http::HeaderValue;
 
 #[tokio::test]
 async fn test_s3_ops_are_customizable() {
     let (http_client, rcvr) = capture_request(None);
-    let sdk_config = SdkConfig::builder()
+    let config = Config::builder()
         .credentials_provider(SharedCredentialsProvider::new(
             Credentials::for_tests_with_session_token(),
         ))
@@ -21,38 +20,27 @@ async fn test_s3_ops_are_customizable() {
         .http_client(http_client.clone())
         .build();
 
-    let client = Client::new(&sdk_config);
-
-    let op = client
-        .list_buckets()
-        .customize()
-        .request_time_for_tests(UNIX_EPOCH + Duration::from_secs(1624036048))
-        .user_agent_for_tests();
+    let client = Client::from_conf(config);
 
     // The response from the fake connection won't return the expected XML but we don't care about
     // that error in this test
-    let _ = op
+    let _ = client
+        .list_buckets()
+        .customize()
+        .mutate_request(|req| {
+            req.headers_mut()
+                .append("test-header", HeaderValue::from_static("test-value"));
+        })
         .send()
         .await
         .expect_err("this will fail due to not receiving a proper XML response.");
 
     let expected_req = rcvr.expect_request();
-    let auth_header = expected_req
+    let test_header = expected_req
         .headers()
-        .get("Authorization")
+        .get("test-header")
         .unwrap()
         .to_owned();
 
-    // This is a snapshot test taken from a known working test result
-    let snapshot_signature =
-        "Signature=c2028dc806248952fc533ab4b1d9f1bafcdc9b3380ed00482f9935541ae11671";
-    assert!(
-        auth_header
-            .to_str()
-            .unwrap()
-            .contains(snapshot_signature),
-        "authorization header signature did not match expected signature: got {}, expected it to contain {}",
-        auth_header.to_str().unwrap(),
-        snapshot_signature
-    );
+    assert_eq!("test-value", test_header.to_str().unwrap(),);
 }
diff --git a/aws/sdk/integration-tests/s3/tests/endpoints.rs b/aws/sdk/integration-tests/s3/tests/endpoints.rs
index 2c31986007..e38269154d 100644
--- a/aws/sdk/integration-tests/s3/tests/endpoints.rs
+++ b/aws/sdk/integration-tests/s3/tests/endpoints.rs
@@ -3,22 +3,20 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-use aws_config::SdkConfig;
 use aws_credential_types::provider::SharedCredentialsProvider;
 use aws_sdk_s3::config::Builder;
 use aws_sdk_s3::config::{Credentials, Region};
-use aws_sdk_s3::Client;
+use aws_sdk_s3::{Client, Config};
 use aws_smithy_runtime::client::http::test_util::{capture_request, CaptureRequestReceiver};
-use std::time::{Duration, UNIX_EPOCH};
 
 fn test_client(update_builder: fn(Builder) -> Builder) -> (CaptureRequestReceiver, Client) {
     let (http_client, captured_request) = capture_request(None);
-    let sdk_config = SdkConfig::builder()
+    let config = Config::builder()
         .credentials_provider(SharedCredentialsProvider::new(Credentials::for_tests()))
         .region(Region::new("us-west-4"))
         .http_client(http_client)
-        .build();
-    let client = Client::from_conf(update_builder(Builder::from(&sdk_config)).build());
+        .with_test_defaults();
+    let client = Client::from_conf(update_builder(config).build());
     (captured_request, client)
 }
 
@@ -69,9 +67,6 @@ async fn multi_region_access_points() {
         .get_object()
         .bucket("arn:aws:s3::123456789012:accesspoint/mfzwi23gnjvgw.mrap")
         .key("blah")
-        .customize()
-        .request_time_for_tests(UNIX_EPOCH + Duration::from_secs(1624036048))
-        .user_agent_for_tests()
         .send()
         .await;
     let captured_request = captured_request.expect_request();
@@ -83,7 +78,7 @@ async fn multi_region_access_points() {
     let auth_header = auth_header.to_str().unwrap();
     // Verifies that the sigv4a signing algorithm was used, that the signing scope doesn't include a region, and that the x-amz-region-set header was signed.
     let expected_start =
-        "AWS4-ECDSA-P256-SHA256 Credential=ANOTREAL/20210618/s3/aws4_request, SignedHeaders=host;x-amz-content-sha256;x-amz-date;x-amz-region-set;x-amz-user-agent, Signature=";
+        "AWS4-ECDSA-P256-SHA256 Credential=ANOTREAL/20090213/s3/aws4_request, SignedHeaders=host;x-amz-content-sha256;x-amz-date;x-amz-region-set;x-amz-user-agent, Signature=";
 
     assert!(
         auth_header.starts_with(expected_start),
@@ -100,8 +95,6 @@ async fn s3_object_lambda() {
         .get_object()
         .bucket("arn:aws:s3-object-lambda:us-east-100:123412341234:accesspoint/myolap")
         .key("s3.txt")
-        .customize()
-        .request_time_for_tests(UNIX_EPOCH + Duration::from_secs(1234567890))
         .send()
         .await
         .unwrap();
diff --git a/aws/sdk/integration-tests/s3/tests/ignore-invalid-xml-body-root.rs b/aws/sdk/integration-tests/s3/tests/ignore-invalid-xml-body-root.rs
index 25a7a34e0b..c9bd3749a3 100644
--- a/aws/sdk/integration-tests/s3/tests/ignore-invalid-xml-body-root.rs
+++ b/aws/sdk/integration-tests/s3/tests/ignore-invalid-xml-body-root.rs
@@ -4,12 +4,11 @@
  */
 
 use aws_credential_types::provider::SharedCredentialsProvider;
+use aws_sdk_s3::Config;
 use aws_sdk_s3::{config::Credentials, config::Region, types::ObjectAttributes, Client};
 use aws_smithy_http::body::SdkBody;
 use aws_smithy_runtime::client::http::test_util::{ReplayEvent, StaticReplayClient};
-use aws_types::SdkConfig;
 use http::header::AUTHORIZATION;
-use std::time::{Duration, UNIX_EPOCH};
 
 const RESPONSE_BODY_XML: &[u8] = b"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<GetObjectAttributesResponse xmlns=\"http://s3.amazonaws.com/doc/2006-03-01/\"><Checksum><ChecksumSHA1>e1AsOh9IyGCa4hLN+2Od7jlnP14=</ChecksumSHA1></Checksum></GetObjectAttributesResponse>";
 
@@ -19,10 +18,9 @@ async fn ignore_invalid_xml_body_root() {
         ReplayEvent::new(http::Request::builder()
              .header("x-amz-object-attributes", "Checksum")
              .header("x-amz-user-agent", "aws-sdk-rust/0.123.test api/test-service/0.123 os/windows/XPSP3 lang/rust/1.50.0")
-             .header("x-amz-date", "20210618T170728Z")
+             .header("x-amz-date", "20090213T233130Z")
              .header("authorization", "AWS4-HMAC-SHA256 Credential=ANOTREAL/20210618/us-east-1/s3/aws4_request, SignedHeaders=host;x-amz-content-sha256;x-amz-date;x-amz-object-attributes;x-amz-security-token;x-amz-user-agent, Signature=0e6ec749db5a0af07890a83f553319eda95be0e498d058c64880471a474c5378")
              .header("x-amz-content-sha256", "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855")
-             .header("x-amz-security-token", "notarealsessiontoken")
              .uri(http::Uri::from_static("https://some-test-bucket.s3.us-east-1.amazonaws.com/test.txt?attributes"))
              .body(SdkBody::empty())
              .unwrap(),
@@ -41,23 +39,21 @@ async fn ignore_invalid_xml_body_root() {
              .unwrap())
     ]);
 
-    let sdk_config = SdkConfig::builder()
+    let config = Config::builder()
         .credentials_provider(SharedCredentialsProvider::new(
             Credentials::for_tests_with_session_token(),
         ))
         .region(Region::new("us-east-1"))
         .http_client(http_client.clone())
+        .with_test_defaults()
         .build();
-    let client = Client::new(&sdk_config);
+    let client = Client::from_conf(config);
 
     let _ = client
         .get_object_attributes()
         .bucket("some-test-bucket")
         .key("test.txt")
         .object_attributes(ObjectAttributes::Checksum)
-        .customize()
-        .request_time_for_tests(UNIX_EPOCH + Duration::from_secs(1624036048))
-        .user_agent_for_tests()
         .send()
         .await
         .unwrap();
diff --git a/aws/sdk/integration-tests/s3/tests/naughty-string-metadata.rs b/aws/sdk/integration-tests/s3/tests/naughty-string-metadata.rs
index 422d64c899..8f43962763 100644
--- a/aws/sdk/integration-tests/s3/tests/naughty-string-metadata.rs
+++ b/aws/sdk/integration-tests/s3/tests/naughty-string-metadata.rs
@@ -4,11 +4,10 @@
  */
 
 use aws_credential_types::provider::SharedCredentialsProvider;
+use aws_sdk_s3::Config;
 use aws_sdk_s3::{config::Credentials, config::Region, primitives::ByteStream, Client};
 use aws_smithy_runtime::client::http::test_util::capture_request;
-use aws_types::SdkConfig;
 use http::HeaderValue;
-use std::time::{Duration, UNIX_EPOCH};
 
 const NAUGHTY_STRINGS: &str = include_str!("blns/blns.txt");
 
@@ -49,14 +48,13 @@ const NAUGHTY_STRINGS: &str = include_str!("blns/blns.txt");
 #[tokio::test]
 async fn test_s3_signer_with_naughty_string_metadata() {
     let (http_client, rcvr) = capture_request(None);
-    let sdk_config = SdkConfig::builder()
+    let config = Config::builder()
         .credentials_provider(SharedCredentialsProvider::new(
             Credentials::for_tests_with_session_token(),
         ))
         .region(Region::new("us-east-1"))
         .http_client(http_client.clone())
-        .build();
-    let config = aws_sdk_s3::config::Builder::from(&sdk_config)
+        .with_test_defaults()
         .force_path_style(true)
         .build();
 
@@ -77,13 +75,7 @@ async fn test_s3_signer_with_naughty_string_metadata() {
         }
     }
 
-    let _ = builder
-        .customize()
-        .request_time_for_tests(UNIX_EPOCH + Duration::from_secs(1624036048))
-        .user_agent_for_tests()
-        .send()
-        .await
-        .unwrap();
+    let _ = builder.send().await.unwrap();
 
     let expected_req = rcvr.expect_request();
     let auth_header = expected_req
@@ -94,7 +86,7 @@ async fn test_s3_signer_with_naughty_string_metadata() {
 
     // This is a snapshot test taken from a known working test result
     let snapshot_signature =
-        "Signature=8dfa41f2db599a9fba53393b0ae5da646e5e452fa3685f7a1487d6eade5ec5c8";
+        "Signature=a5115604df66219874a9e5a8eab4c9f7a28c992ab2d918037a285756c019f3b2";
     assert!(
         auth_header
             .to_str()
diff --git a/aws/sdk/integration-tests/s3/tests/no_auth.rs b/aws/sdk/integration-tests/s3/tests/no_auth.rs
index f7e8f477ea..f3029e4a1d 100644
--- a/aws/sdk/integration-tests/s3/tests/no_auth.rs
+++ b/aws/sdk/integration-tests/s3/tests/no_auth.rs
@@ -3,6 +3,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+use aws_sdk_s3::{Client, Config};
 use aws_smithy_protocol_test::MediaType;
 use aws_smithy_runtime::client::http::test_util::dvr::ReplayingClient;
 use aws_smithy_runtime::test_util::capture_test_logs::capture_test_logs;
@@ -18,15 +19,16 @@ async fn list_objects() {
         .region("us-east-1")
         .load()
         .await;
-    let client = aws_sdk_s3::Client::new(&config);
+    let config = Config::from(&config)
+        .to_builder()
+        .with_test_defaults()
+        .build();
+    let client = aws_sdk_s3::Client::from_conf(config);
 
     let result = client
         .list_objects()
         .bucket("gdc-organoid-pancreatic-phs001611-2-open")
         .max_keys(3)
-        .customize()
-        .remove_invocation_id_for_tests()
-        .user_agent_for_tests()
         .send()
         .await;
     dbg!(result).expect("success");
@@ -49,15 +51,16 @@ async fn list_objects_v2() {
         .region("us-east-1")
         .load()
         .await;
-    let client = aws_sdk_s3::Client::new(&config);
+    let config = Config::from(&config)
+        .to_builder()
+        .with_test_defaults()
+        .build();
+    let client = Client::from_conf(config);
 
     let result = client
         .list_objects_v2()
         .bucket("gdc-organoid-pancreatic-phs001611-2-open")
         .max_keys(3)
-        .customize()
-        .remove_invocation_id_for_tests()
-        .user_agent_for_tests()
         .send()
         .await;
     dbg!(result).expect("success");
@@ -79,15 +82,16 @@ async fn head_object() {
         .region("us-east-1")
         .load()
         .await;
-    let client = aws_sdk_s3::Client::new(&config);
+    let config = Config::from(&config)
+        .to_builder()
+        .with_test_defaults()
+        .build();
+    let client = Client::from_conf(config);
 
     let result = client
         .head_object()
         .bucket("gdc-organoid-pancreatic-phs001611-2-open")
         .key("0431cddc-a418-4a79-a34d-6c041394e8e4/a6ddcc84-8e4d-4c68-885c-2d51168eec97.FPKM-UQ.txt.gz")
-        .customize()
-        .remove_invocation_id_for_tests()
-        .user_agent_for_tests()
         .send()
         .await;
     dbg!(result).expect("success");
@@ -109,15 +113,16 @@ async fn get_object() {
         .region("us-east-1")
         .load()
         .await;
-    let client = aws_sdk_s3::Client::new(&config);
+    let config = Config::from(&config)
+        .to_builder()
+        .with_test_defaults()
+        .build();
+    let client = Client::from_conf(config);
 
     let result = client
         .get_object()
         .bucket("gdc-organoid-pancreatic-phs001611-2-open")
         .key("0431cddc-a418-4a79-a34d-6c041394e8e4/a6ddcc84-8e4d-4c68-885c-2d51168eec97.FPKM-UQ.txt.gz")
-        .customize()
-        .remove_invocation_id_for_tests()
-        .user_agent_for_tests()
         .send()
         .await;
     dbg!(result).expect("success");
diff --git a/aws/sdk/integration-tests/s3/tests/normalize-uri-path.rs b/aws/sdk/integration-tests/s3/tests/normalize-uri-path.rs
index ae8426d16c..a044a3e921 100644
--- a/aws/sdk/integration-tests/s3/tests/normalize-uri-path.rs
+++ b/aws/sdk/integration-tests/s3/tests/normalize-uri-path.rs
@@ -3,25 +3,24 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-use aws_config::SdkConfig;
 use aws_credential_types::provider::SharedCredentialsProvider;
 use aws_sdk_s3::primitives::ByteStream;
+use aws_sdk_s3::Config;
 use aws_sdk_s3::{config::Credentials, config::Region, Client};
 use aws_smithy_runtime::client::http::test_util::capture_request;
-use std::time::{Duration, UNIX_EPOCH};
 
 #[tokio::test]
 async fn test_operation_should_not_normalize_uri_path() {
     let (http_client, rx) = capture_request(None);
-    let sdk_config = SdkConfig::builder()
+    let config = Config::builder()
         .credentials_provider(SharedCredentialsProvider::new(
             Credentials::for_tests_with_session_token(),
         ))
         .region(Region::new("us-east-1"))
         .http_client(http_client.clone())
+        .with_test_defaults()
         .build();
-
-    let client = Client::new(&sdk_config);
+    let client = Client::from_conf(config);
 
     let bucket_name = "test-bucket-ad7c9f01-7f7b-4669-b550-75cc6d4df0f1";
 
@@ -30,9 +29,6 @@ async fn test_operation_should_not_normalize_uri_path() {
         .bucket(bucket_name)
         .key("a/.././b.txt") // object key with dot segments
         .body(ByteStream::from_static("Hello, world".as_bytes()))
-        .customize()
-        .request_time_for_tests(UNIX_EPOCH + Duration::from_secs(1669257290))
-        .user_agent_for_tests()
         .send()
         .await
         .unwrap();
@@ -45,7 +41,7 @@ async fn test_operation_should_not_normalize_uri_path() {
     let expected_uri = "/a/.././b.txt";
     assert_eq!(actual_uri, expected_uri);
 
-    let expected_sig = "Signature=4803b8b8c794b5ecc055933befd7c5547f8bf6585bb18e4ae33ff65220d5cdd7";
+    let expected_sig = "Signature=2ac540538c84dc2616d92fb51d4fc6146ccd9ccc1ee85f518a1a686c5ef97b86";
     assert!(
         actual_auth.contains(expected_sig),
         "authorization header signature did not match expected signature: expected {} but not found in {}",
diff --git a/aws/sdk/integration-tests/s3/tests/query-strings-are-correctly-encoded.rs b/aws/sdk/integration-tests/s3/tests/query-strings-are-correctly-encoded.rs
index 9f688fe69b..55c68f6155 100644
--- a/aws/sdk/integration-tests/s3/tests/query-strings-are-correctly-encoded.rs
+++ b/aws/sdk/integration-tests/s3/tests/query-strings-are-correctly-encoded.rs
@@ -3,25 +3,23 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-use aws_config::SdkConfig;
 use aws_credential_types::provider::SharedCredentialsProvider;
 use aws_sdk_s3::config::{Credentials, Region};
-use aws_sdk_s3::Client;
+use aws_sdk_s3::{Client, Config};
 use aws_smithy_runtime::client::http::test_util::capture_request;
-use std::time::{Duration, UNIX_EPOCH};
 
 #[tokio::test]
 async fn test_s3_signer_query_string_with_all_valid_chars() {
     let (http_client, rcvr) = capture_request(None);
-    let sdk_config = SdkConfig::builder()
+    let config = Config::builder()
         .credentials_provider(SharedCredentialsProvider::new(
             Credentials::for_tests_with_session_token(),
         ))
         .region(Region::new("us-east-1"))
         .http_client(http_client.clone())
+        .with_test_defaults()
         .build();
-
-    let client = Client::new(&sdk_config);
+    let client = Client::from_conf(config);
 
     // Generate a string containing all printable ASCII chars
     let prefix: String = (32u8..127).map(char::from).collect();
@@ -32,9 +30,6 @@ async fn test_s3_signer_query_string_with_all_valid_chars() {
         .list_objects_v2()
         .bucket("test-bucket")
         .prefix(&prefix)
-        .customize()
-        .request_time_for_tests(UNIX_EPOCH + Duration::from_secs(1624036048))
-        .user_agent_for_tests()
         .send()
         .await;
 
@@ -47,7 +42,7 @@ async fn test_s3_signer_query_string_with_all_valid_chars() {
 
     // This is a snapshot test taken from a known working test result
     let snapshot_signature =
-        "Signature=647aa91c7f91f1f1c498ef376fea370b48d0cd8c80a53c8e2cd64e3fc527a5e0";
+        "Signature=9a931d20606f93fa4e5553602866a9b5ccac2cd42b54ae5a4b17e4614fb443ce";
     assert!(
         auth_header
             .to_str()
diff --git a/aws/sdk/integration-tests/s3/tests/signing-it.rs b/aws/sdk/integration-tests/s3/tests/signing-it.rs
index 1b3e59e373..22dcf7c3d9 100644
--- a/aws/sdk/integration-tests/s3/tests/signing-it.rs
+++ b/aws/sdk/integration-tests/s3/tests/signing-it.rs
@@ -3,39 +3,35 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-use aws_config::SdkConfig;
 use aws_credential_types::provider::SharedCredentialsProvider;
 use aws_sdk_s3::config::{Credentials, Region};
-use aws_sdk_s3::Client;
+use aws_sdk_s3::{Client, Config};
 use aws_smithy_http::body::SdkBody;
 use aws_smithy_runtime::client::http::test_util::{ReplayEvent, StaticReplayClient};
-use std::time::{Duration, UNIX_EPOCH};
 
 #[tokio::test]
 async fn test_signer() {
     let http_client = StaticReplayClient::new(vec![ReplayEvent::new(
         http::Request::builder()
-            .header("authorization", "AWS4-HMAC-SHA256 Credential=ANOTREAL/20210618/us-east-1/s3/aws4_request, SignedHeaders=host;x-amz-content-sha256;x-amz-date;x-amz-security-token;x-amz-user-agent, Signature=ae78f74d26b6b0c3a403d9e8cc7ec3829d6264a2b33db672bf2b151bbb901786")
+            .header("authorization", "AWS4-HMAC-SHA256 Credential=ANOTREAL/20090213/us-east-1/s3/aws4_request, SignedHeaders=host;x-amz-content-sha256;x-amz-date;x-amz-user-agent, Signature=27e3f59ec3cffaa10e4f1c92112e8fb62d468a04cd32be39e68215f830404dbb")
             .uri("https://test-bucket.s3.us-east-1.amazonaws.com/?list-type=2&prefix=prefix~")
             .body(SdkBody::empty())
             .unwrap(),
         http::Response::builder().status(200).body(SdkBody::empty()).unwrap(),
     )]);
-    let sdk_config = SdkConfig::builder()
+    let config = Config::builder()
         .credentials_provider(SharedCredentialsProvider::new(
             Credentials::for_tests_with_session_token(),
         ))
         .region(Region::new("us-east-1"))
         .http_client(http_client.clone())
+        .with_test_defaults()
         .build();
-    let client = Client::new(&sdk_config);
+    let client = Client::from_conf(config);
     let _ = client
         .list_objects_v2()
         .bucket("test-bucket")
         .prefix("prefix~")
-        .customize()
-        .request_time_for_tests(UNIX_EPOCH + Duration::from_secs(1624036048))
-        .user_agent_for_tests()
         .send()
         .await;
 
diff --git a/aws/sdk/integration-tests/s3control/Cargo.toml b/aws/sdk/integration-tests/s3control/Cargo.toml
index 723f8c964a..bd1923c141 100644
--- a/aws/sdk/integration-tests/s3control/Cargo.toml
+++ b/aws/sdk/integration-tests/s3control/Cargo.toml
@@ -10,10 +10,14 @@ publish = false
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[features]
+default = ["test-util"]
+test-util = []
+
 [dev-dependencies]
 aws-credential-types = { path = "../../build/aws-sdk/sdk/aws-credential-types", features = ["test-util"] }
 aws-http = { path = "../../build/aws-sdk/sdk/aws-http" }
-aws-sdk-s3control = { path = "../../build/aws-sdk/sdk/s3control" }
+aws-sdk-s3control = { path = "../../build/aws-sdk/sdk/s3control", features = ["test-util"] }
 aws-smithy-async = { path = "../../build/aws-sdk/sdk/aws-smithy-async" }
 aws-smithy-runtime = { path = "../../build/aws-sdk/sdk/aws-smithy-runtime", features = ["client", "test-util"] }
 aws-smithy-http = { path = "../../build/aws-sdk/sdk/aws-smithy-http" }
diff --git a/aws/sdk/integration-tests/s3control/tests/signing-it.rs b/aws/sdk/integration-tests/s3control/tests/signing-it.rs
index b94e397170..242f2f2d78 100644
--- a/aws/sdk/integration-tests/s3control/tests/signing-it.rs
+++ b/aws/sdk/integration-tests/s3control/tests/signing-it.rs
@@ -5,41 +5,36 @@
 
 use aws_credential_types::provider::SharedCredentialsProvider;
 use aws_sdk_s3control::config::{Credentials, Region};
-use aws_sdk_s3control::Client;
+use aws_sdk_s3control::{Client, Config};
 use aws_smithy_http::body::SdkBody;
 use aws_smithy_runtime::client::http::test_util::{ReplayEvent, StaticReplayClient};
-use aws_types::SdkConfig;
-use std::time::{Duration, UNIX_EPOCH};
 
 #[tokio::test]
 async fn test_signer() {
     let http_client = StaticReplayClient::new(vec![ReplayEvent::new(
         http::Request::builder()
             .header("authorization",
-                    "AWS4-HMAC-SHA256 Credential=ANOTREAL/20211112/us-east-1/s3/aws4_request, \
-                    SignedHeaders=host;x-amz-account-id;x-amz-content-sha256;x-amz-date;x-amz-security-token;x-amz-user-agent, \
-                    Signature=ac58c2246428af711ab7bca30c704a2b6a5fd7451cf83f3bceff177f1636e277")
+                    "AWS4-HMAC-SHA256 Credential=ANOTREAL/20090213/us-east-1/s3/aws4_request, \
+                    SignedHeaders=host;x-amz-account-id;x-amz-content-sha256;x-amz-date;x-amz-user-agent, \
+                    Signature=0102a74cb220f8445c4efada17660572ff813e07b524032ec831e8c2514be903")
             .uri("https://test-bucket.s3-control.us-east-1.amazonaws.com/v20180820/accesspoint")
             .body(SdkBody::empty())
             .unwrap(),
         http::Response::builder().status(200).body(SdkBody::empty()).unwrap(),
     )]);
-    let sdk_config = SdkConfig::builder()
+    let config = Config::builder()
         .credentials_provider(SharedCredentialsProvider::new(
             Credentials::for_tests_with_session_token(),
         ))
         .http_client(http_client.clone())
         .region(Region::new("us-east-1"))
+        .with_test_defaults()
         .build();
-    let client = Client::new(&sdk_config);
+    let client = Client::from_conf(config);
 
     let _ = client
         .list_access_points()
         .account_id("test-bucket")
-        .customize()
-        .request_time_for_tests(UNIX_EPOCH + Duration::from_secs(1636751225))
-        .user_agent_for_tests()
-        .remove_invocation_id_for_tests()
         .send()
         .await
         .expect_err("empty response");
diff --git a/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/config/ServiceConfigGenerator.kt b/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/config/ServiceConfigGenerator.kt
index 455942df49..a6379bb4b4 100644
--- a/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/config/ServiceConfigGenerator.kt
+++ b/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/config/ServiceConfigGenerator.kt
@@ -401,7 +401,7 @@ class ServiceConfigGenerator(
             testUtilOnly.render(this)
             Attribute.AllowUnusedMut.render(this)
             docs("Apply test defaults to the builder")
-            rustBlock("pub fn set_test_defaults(&mut self) -> &mut Self") {
+            rustBlock("pub fn apply_test_defaults(&mut self) -> &mut Self") {
                 customizations.forEach { it.section(ServiceConfig.DefaultForTests("self"))(this) }
                 rust("self")
             }
@@ -410,7 +410,7 @@ class ServiceConfigGenerator(
             Attribute.AllowUnusedMut.render(this)
             docs("Apply test defaults to the builder")
             rustBlock("pub fn with_test_defaults(mut self) -> Self") {
-                rust("self.set_test_defaults(); self")
+                rust("self.apply_test_defaults(); self")
             }
 
             docs("Builds a [`Config`].")