Audi S4/S5 High-Flow Catted Downpipe 2017-2025 (EA839 B9) | WSTN Performance

More flow, more sound and more power from the EA839 3.0T V6. WSTN Performance high-flow catted downpipe for the Audi S4 and S5 (B9, EA839 3.0 turbo V6), covering the S4 Sedan and Avant and the S5 Coupe, Sportback and Cabriolet. It replaces the restrictive factory downpipe with a free-flowing stainless steel downpipe that stays catted, heat shielded as standard. The result is more flow, a deeper and fuller V6 note, more power with quicker turbo response, and a cooler engine bay. Select your car below, enter your VIN, and we double check fitment before your order ships. Why Upgrade? ✓ More Flow: A free-flowing, high-flow catted stainless steel downpipe replaces the restrictive factory downpipe directly behind the turbo, so the exhaust gas has an easier path out of the turbo and into the rest of the system. ✓ More Sound: A deeper, fuller EA839 V6 note when you are on the throttle and more character when you lift off, while the downpipe stays catted. The sound the factory downpipe holds back. ✓ More Power: Less restriction right behind the turbo means it spools quicker and the EA839 makes more power through the rev range. ✓ Less Heat: Heat shielding fitted as standard keeps the heat inside the pipe, so your engine bay runs cooler than it would without it. ✓ Perfect Fit: Use the car selector on this page to confirm your model and year, and enter your VIN so we can double check fitment. If entered, your VIN is submitted with your order at checkout. Key Features & Specs Material: T304 stainless steel Heat shielding: Fitted as standard along the full length, from the turbo flange to both outlet flanges Sensor provision: Oxygen sensor bung on the turbo-side pipe. OPF vehicles receive the necessary sensor provisions as well. Configuration: High-flow catted Fitment & Compatibility ✓ Audi S4 Sedan (B9) / 2017-2025 / EA839 3.0T ✓ Audi S4 Avant (B9) / 2017-2025 / EA839 3.0T ✓ Audi S5 Coupe (B9) / 2017-2024 / EA839 3.0T ✓ Audi S5 Sportback (B9) / 2017-2025 / EA839 3.0T ✓ Audi S5 Cabriolet (B9) / 2017-2024 / EA839 3.0T Check it fits your car Use the fitment selector on this page to confirm your exact make, model, and year before ordering. What's In the Box ✓ 1 x WSTN Performance Audi S4/S5 B9 EA839 high-flow catted downpipe with heat shielding, 1 piece Installation ✓ Replaces the factory downpipe between the turbo and the factory exhaust joints ✓ Connects with a V-band flange at the turbo end and a 3-bolt flange on each outlet leg ✓ Professional installation recommended Heat Shielding ✓ Cooler engine bay: Heat shielding stops the heat coming off the pipe from spreading into the bay, so your engine bay runs cooler than it would without it. ✓ Less heat soak: Hoses, wiring, sensors and the rubber and plastic parts near the exhaust take on less heat, which helps them last. ✓ Factory approach: The same principle used on factory exhaust systems, a barrier between hot metal and the rest of the bay. ✓ Heat stays in the pipe: Keeping heat in the exhaust stream instead of radiating it out supports flow through the pipe. Why WSTN Performance? ✓ Fitment checked twice: Use the car selector to confirm your model and year and enter your VIN. We check it again before your order ships. ✓ Quality you know: Built to the same standard as the big brands you already know. ✓ Australian based support: Real people, real enthusiasts. ✓ Worldwide delivery, correct fitment everywhere: Fitments differ between markets and we check for this. Our images may not always show the international version, but what you receive will be the correct fitment for your car. ✓ 1 year warranty: Every product is covered by our 1 year WSTN Performance warranty. ✓ Run by car enthusiasts: We are excited to see our parts on your car. Warranty / Shipping DISCLAIMER WSTN Performance components are designed for track and competition use only. 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. If your product is made to order, the product page shows how long it takes to manufacture, and at checkout you will see how many days delivery takes after manufacturing. If it is in stock, the checkout page will show you when it will arrive. 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 Sound clip Coming soon.