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3 Inch Turbo Downpipe for Subaru GT35 GT35R High-Flow Exhaust Performance - KSP Performance
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EGR Valve compatible for Mercedes-Benz GL350 ML350 E350 GLS350d E350 S350 3.0L S63 AMG 5.5L
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Catalytic Converter compatible for Honda CR-V 2015-2016 2.4l674-145 Direct Replacement
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Front Left Exhaust Manifold w/ Catalytic Converter compatible for Ford Escape 3.0L V6 01-06
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Secondary Air Injection Check Valve compatible for Chevy Cobalt compatible for Pontiac G5 compatible for Saturn
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Secondary Air Injection Check Valve compatible for Chevy Equinox GMC Terrain 101392-5170
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Catalytic Converter compatible for Subaru WRX 2.0L 2015-202144612-AA771 44612AA771
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Vapor Canister compatible for Toyota Corolla Vapor Canister 2003-04 77740-02121 911-631
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2001-2016 Chevy GMC Duramax 6.6L Downpipe for LB7 LLY LBZ LMM LML - KSP Performance
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Exhaust Upgrades: Sound, Flow and Staying Legal
Written by the PickupChain team · Last reviewed October 17, 2026
Most truck exhaust upgrades are about sound and a small gain in flow. Axle-back systems replace only the muffler and tips and are the simplest. Cat-back systems replace everything behind the catalytic converter and give a bigger change in sound and flow.
Emissions parts are a different matter. Catalytic converters, diesel particulate filters and EGR systems are required by federal law on road vehicles. Removing them is illegal for street use in all 50 states and can fail inspection. Only buy emissions parts that are listed as legal replacements for your state.
California and states that follow CARB rules require an Executive Order (EO) number for many aftermarket parts. Look for CARB-legal labels if you live there.
Frequently Asked Questions
+Cat-back or axle-back exhaust?
Axle-back systems are cheaper, quicker to install and mainly change the sound. Cat-back systems replace more piping, change sound and flow more noticeably and often add a little power.
+Will a new exhaust cause drone on the highway?
Some aggressive systems produce a low hum at cruising speed called drone. Look for systems with resonators or descriptions that mention reduced drone if you drive long distances.
+Do I need a tune after an exhaust upgrade?
A cat-back or axle-back exhaust does not require a tune. Headers and downpipes often do, and they may affect emissions compliance.