Milltek HJS Hi-Flow Sports Cat and Downpipe - Audi S4 B9 - SSXAU673

Milltek HJS Hi-Flow Sports Cat and Downpipe for the Audi S4 B9

Engineered as a direct replacement for the factory downpipe, mandrel-bent throughout to maintain flow and fitted to the OE mounting points.

Key Features

• Premium Materials: T304Lstainless steel for durability and lasting corrosion resistance.
• Enhanced Performance: 2.50" (63.50mm) mandrel-bent pipework improves exhaust flow for sharper throttle response.
• Direct Fitment: engineered as a bolt-on replacement for the factory system.
• Race Use: intended for track and off-road use— check local regulations before road use.

Technical Specifications

• Pipe Diameter: 2.50" (63.50mm)
• Material: T304L Stainless Steel
• System Type: HJS Hi-Flow Sports Cat and Downpipe
• Fitting Time: 1.00 to 1.50 hours

Compatibility

• 2017 and later S5 3.0 V6 Turbo Sportback B9 (Non Sport Diff Models Only) - Left Hand Drive Cars Only
• 2017 and later S5 3.0 V6 Turbo Coupe/Cabrio B9 (Non Sport Diff Models Only) - Left Hand Drive Cars Only
• 2017 and later S5 3.0 V6 Turbo Coupe Only B9 (Sport Diff Models Only & Without Brace Bars) - Left Hand Drive Cars Only
• 2017 and later S5 3.0 V6 Turbo Sportback B9 (Sport Diff Models Only & without Brace Bars) - Left Hand Drive Cars Only
• 2017 and later S5 3.0 V6 Turbo Sportback B9 (Sport Diff Models Only & WITH Brace Bars) - Left Hand Drive Cars Only
• 2017 and later S5 3.0 V6 Turbo Coupe Only B9 (Sport Diff Models Only & WITH Brace Bars) - Left Hand Drive Cars Only
• 2016 and later S4 3.0 Turbo V6 B9 - Saloon/Sedan & Avant (ONLY - Non Sport Diff Models) - Left Hand Drive Cars Only
• 2016 and later S4 3.0 Turbo V6 B9 - Saloon/Sedan & Avant (ONLY - Sport Diff Models Only & Without Brace Bars) - Left Hand Drive Cars Only

Why Choose Milltek?

Every system is precision-built to deliver the sound, flow, and quality that define the Milltek difference.

Designed and manufactured in the UK with 40+ years of performance exhaust heritage. Tested at the Nurburgring.

Specifications

• Pipe diameter: 63.5mm (2.50")
• Fitting time: 1 to 1.5 hours, including removing the factory system
• Off-road / competition use only. Not legal for use on public roads in the US.

Fitment

• Audi > S4 > 3.0 Turbo V6 B9 - Saloon/Sedan & Avant (ONLY - Non Sport Diff Models) - Left Hand Drive Cars Only > 2016 and Later
• Audi > S4 > 3.0 Turbo V6 B9 - Saloon/Sedan & Avant (ONLY - Sport Diff Models Only & Without Brace Bars) - Left Hand Drive Cars Only > 2016 and Later
• Audi > S5 > 3.0 V6 Turbo Coupe Only B9 (Sport Diff Models Only & WITH Brace Bars) - Left Hand Drive Cars Only > 2017 and Later
• Audi > S5 > 3.0 V6 Turbo Coupe Only B9 (Sport Diff Models Only & Without Brace Bars) - Left Hand Drive Cars Only > 2017 and Later
• Audi > S5 > 3.0 V6 Turbo Coupe/Cabrio B9 (Non Sport Diff Models Only) - Left Hand Drive Cars Only > 2017 and Later
• Audi > S5 > 3.0 V6 Turbo Sportback B9 (Non Sport Diff Models Only) - Left Hand Drive Cars Only > 2017 and Later
• Audi > S5 > 3.0 V6 Turbo Sportback B9 (Sport Diff Models Only & WITH Brace Bars) - Left Hand Drive Cars Only > 2017 and Later
• Audi > S5 > 3.0 V6 Turbo Sportback B9 (Sport Diff Models Only & without Brace Bars) - Left Hand Drive Cars Only > 2017 and Later

• Free US shipping on orders over $250.
• Free pickup at our Dallas shop, usually ready within 24 hours.
• Unused parts can be returned within 30 days. Tunes, opened electronics, merch and installed parts are final sale.
• Want it installed? Book the install at thegbmotors.com.

Full details are on our shipping and returns page.