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Exhaust› Exhaust Pipes, Systems and Components

Milltek Sport

Cat-Back Exhaust System

Name: Cat-Back Exhaust System
Brand: Milltek Sport
SKU: SSXAU554

$4,588.10

SKU: SSXAU554

Free Shipping over $200

$100 Minimum Order

Non-Returnable Item

DIY PRO SHOP

Moderate — 2–4 hours

Overview

These downpipes feature a larger diameter than standard OEM parts, allowing more gas to exit the engine and increasing efficiency. When combined with a Hi-Flow Sports Cat, they contribute to a significant increase in performance and a noticeable difference in sound aesthetic.

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Fabricated with a larger 76mm diameter compared to standard OEM parts, these downpipes provide increased space for exhaust gases to exit the engine, thereby improving efficiency and performance. When paired with the integrated Hi-Flow Sports Catalysts, a noticeable uplift in both performance figures and sound quality can be expected.

Vehicle Symptoms

Reduced engine power during acceleration
Exhaust drone at cruising speeds
Rattling noise from under the car
Sulfur or rotten egg smell from exhaust
Engine feels sluggish above 3000 RPM

Diagnostic Codes

P0420 – Cat Sys Efficiency Below Threshold (B1)
P0430 – Cat Sys Efficiency Below Threshold (B2)

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Milltek SSXAU554 review and sound clip

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

Brand	Milltek Sport
Part Number	SSXAU554
Category	Exhaust

Videos

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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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