Exhaust› Exhaust Pipes, Systems and Components

Redstar Exhaust

3.0L TFSI Turbo Downpipe

$480.00

SKU: RS.B9S4.B9S5.DP

In Stock
In Stock
Ships by Aug 31
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The Redstar Exhaust downpipe is a performance-focused upgrade for 2017+ Audi B9 S4 and S5 3.0L TFSI Turbo models. It features a large-bore, flow-optimized design crafted from 2.0mm wall 304L stainless steel for improved exhaust efficiency and throttle response.

Constructed with 100% TIG-welded seams and OEM-spec V-band flanges, this downpipe provides a direct-fit installation with factory mounting points. It is intended for off-road and motorsport use only.
Show original supplier description
The Redstar Exhaust downpipe offers a significant performance enhancement for 2017+ Audi S4 and S5 B9/B9.5 3.0T vehicles. By utilizing a large-bore layout with smooth, flow-optimized transitions, it effectively reduces exhaust backpressure to achieve faster turbo spool-up, improved throttle response, and a more aggressive exhaust note while helping to lower under-hood temperatures. Each unit is built from premium 304L stainless steel with a 2.0mm wall thickness, 100% TIG-welded and back-purged for structural integrity. The design incorporates OEM-spec V-band flanges and retains all factory brackets and mounts, ensuring a 100% bolt-on installation. ECU tuning is highly recommended to ensure optimal performance and proper engine calibration; the manufacturer specifically suggests consulting with Purisic Performance. Optional hardware includes GESI GEN2 400cpsi catalytic converters, OE-style heat shielding with ceramic inner liners, and tunable O2 sensor spacers to help prevent engine light conditions. Please note that this product is for off-road and motorsport use only.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Specifications

BrandRedstar Exhaust
Part NumberRS.B9S4.B9S5.DP
CategoryExhaust

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Returns & Fitment

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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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

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