Audi S4/S5 B9 Catless Downpipe 2017-2023 (EA839 B9) | WSTN Performance

The EA839 is one of the best inline-six architectures Audi has made. A restrictive stock downpipe is a strange way to celebrate it. WSTN Performance catless downpipe for the Audi S4 and S5 B9. Perth quality-checked and dispatched worldwide. Why Upgrade? ✓ EA839 Unleashed: Removes the restrictive factory catalytic converter to maximise flow through the EA839 3.0T V6. Gains are felt from low in the rev range, not just at peak. ✓ Improved Turbo Response: With the restriction gone, turbo spool improves — response sharpens and power comes on earlier. ✓ T304 Stainless Construction: Corrosion-resistant T304 stainless steel built for sustained heat load of the EA839's twin-scroll turbo. ✓ Hand Built to Order: Built to your order and quality checked in Perth WA before dispatch. Not pulled from shelf stock. Key Features & Specs Material: T304 stainless steel Construction: TIG-welded Catalyst: None (catless — track/competition use) Finish: Natural brushed stainless Branding: WSTN Performance logo Fitment & Compatibility ✓ Audi S4 / S5 (B9) / 2017–2023 / EA839 3.0T V6 Confirm fitment before purchase Add your make, model, year, and VIN in the cart notes at checkout so we can match against our compatibility database before dispatch. Wrong fitment costs everyone time we'd rather not waste. What's In the Box ✓ 1 x WSTN Performance Audi S4/S5 B9 Catless Downpipe with WSTN Performance logo Installation Difficulty: 4 of 5 — Turbo downpipe replacement, specialist installation required Time: 3 to 5 Hours Mounting: OEM flange replacement at turbo outlet Technical Note: Catless unit removes factory catalytic converter. Track and competition use only. Compliance with local emissions regulations is the buyer's responsibility. Confirm fitment before purchase Add your make, model, year, and VIN in the cart notes at checkout so we can match against our compatibility database before dispatch. Wrong fitment costs everyone time we'd rather not waste. Warranty / Shipping DISCLAIMER WSTN Performance components are designed for track and competition use. To protect your build and ensure a perfect finish, we recommend professional installation by a certified specialist/workshop. It is the buyer's responsibility to ensure modifications comply with local regulations. WARRANTY We stand behind every product we sell. All WSTN Performance products carry a 1 year WSTN Performance warranty as standard. This covers any manufacturing defects, giving you total peace of mind that your upgrade is built to last. View our full Warranty policy page here. SHIPPING We offer tracked worldwide shipping on our entire catalogue. Products marked as "Built to Order" are completed in 3-5 weeks (check the product page as lead times may vary) and personally dispatched from our Perth WA facility. View our full Shipping policy page here. RETURNS We offer returns on all products if items are damaged or there is something wrong. If we ever make a mistake, we'll cover the return shipping to make it right. View our full Return policy page here. SUPPORT Need a hand with fitment, shipping, or a return? Our Perth-based team is here to help you get your build perfect. Email: contact@wstnperformance.com