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Stillen

Cat-Back Exhaust System

$1,720.73 $1,517.88 Save $202.85

SKU: 504377

In Stock
In Stock
Ships by Aug 4
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30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Description

The Stillen 504377 is a premium cat-back exhaust system engineered to enhance the performance and sound of your 2009-2013 Infiniti G37 Sedan or 2015 Q40. It features a dual split rear exit configuration, complemented by polished 304SS dual wall tips that deliver an aggressive aesthetic. The design focuses on improving airflow to unlock substantial horsepower and torque gains, verified by dyno testing for a significant increase at the wheels. Users can expect an authoritative tone under throttle, while maintaining a more luxurious and quiet cabin feel during idle and cruising. Installation is described as straightforward, with the new system fitting together well.

MIA's Description

The Stillen 504377 is a cat-back exhaust system designed for the 2009-2013 Infiniti G37 Sedan and the 2015 Q40. It features a dual split rear exit with polished 304 stainless steel dual wall tips. This system is constructed from 304 stainless steel and is mandrel-bent for durability.

The exhaust provides a noticeable increase in horsepower and torque, with a sound profile that is mild at idle, aggressive under throttle, and suitable for highway cruising. It is compatible with both RWD and AWD models.

Fitment

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Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.

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Specifications

BrandStillen
Part Number504377
CategoryExhaust

Buy with Confidence

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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