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Milltek Sport

Large Bore Downpipe and Hi-Flow Sports Catalytic Converter

$1,586.20 $1,542.94 Save $43.26

SKU: SSXAU381

Special Order
Special Order
Ships in 4–6 weeks
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The Milltek Sport SSXAU381 is a large bore downpipe and hi-flow sports catalytic converter system. It is constructed from aerospace grade type 304, non-magnetic stainless steel, ensuring durability and resistance to discoloration. The system features mandrel-bent piping for optimized gas flow and an enlarged bore diameter to maximize performance without sacrificing mid-range torque.
Show original supplier description
The Milltek Sport SSXAU381 is a large bore downpipe and hi-flow sports catalytic converter system, crafted from aerospace grade type 304, non-magnetic stainless steel. This material choice ensures superior longevity and resistance to discoloration compared to standard materials. The system is designed with mandrel-bent piping, which guarantees consistent radius bends for optimized gas flow and increased efficiency. Furthermore, the bore diameters are enlarged over stock specifications to deliver ultimate performance gains without a loss in mid-range torque. It is crucial to note that a Stage 2 ECU remap is required for this system to function correctly and safely. The use of de-cat or sports cat components is intended for off-road or motorsport use only and will prevent the vehicle from passing an MOT test. Only EC type-approved components are legal for road use. This specific configuration, SSXAU381, is compatible with the Audi A3 8V 2.0 TFSI quattro Sedan (US-only) from 2014-2020, the Audi S3 8V/8V.2 Sportback (Non-GPF Equipped Models Only) from 2013-2018, and the Audi S3 8V/8V.2 Saloon & Cabrio (Non-GPF Equipped Models Only) from 2013-2018.

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

BrandMilltek Sport
Part NumberSSXAU381
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.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

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