Maximize the performance of your Audi S4 B9 3.0 TFSI with the ASM Performance Front Downpipe – available in Sport Cat and De-Cat configurations. Engineered for drivers seeking sharper turbo response, increased power, and a more dynamic exhaust tone, this is one of the most effective performance upgrades for the S4 platform.
Constructed from high-grade T304 stainless steel, each downpipe is TIG-welded for precision and durability. The Sport Cat version includes a 200-cell high-flow catalytic converter, providing a perfect balance between performance and emission control. For those who prioritize unrestricted power, the De-Cat version offers maximum exhaust flow and turbo efficiency — ideal for off-road or track applications.
Our sports exhaust selection is fully backed with a lifetime warranty, ensuring quality assurance.
Features & Details
- Substantial power increase
- Specially designed smooth transition for optimized flow
- Improved spool up speed and throttle response
- Extended turbo lifespan
- Lowering under hood temperature
- Enhanced performance sound
- 100% Easy and secure bolt-on installation
- Fully tig welded and back purged crafting
- Top-tier 304L stainless steel with a 2.00mm thick wall
- Compliant with both LHD and RHD vehicles
- Backed by a lifetime warranty
These will fit the following models:
- Audi S4 B9
- Audi S5 B9
What is the difference between a sport cat and a decat?
Sport Cat Downpipes
Catalytic Converter Included: Sport cat downpipes include a high-flow catalytic converter. This helps reduce exhaust emissions while still allowing for increased flow compared to standard catalytic converters.
Emissions Compliance: They are designed to be street-legal in many areas, as they still filter harmful emission, though regulations can vary by region.
Performance: Sport cat downpipes strike a balance between performance and emissions compliance. They offer a noticeable increase in horsepower and torque compared to stock downpipes, but might not be as free-flowing as decat downpipes.
Sound: The sport cat downpipes provide a moderate increase in exhaust sound over the stock system.
Decat Downpipes
No Catalytic Converter: Decat downpipes eliminate the catalytic converter entirely, resulting in zero filtration of exhaust gases.
Higher Performance: They allow for maximum exhaust flow, which can result in significant performance gains, particularly for turbocharged engines.
Emissions Non-Compliance: Decat downpipes are typically illegally for street use in most regions due to their complete lack of emissions control. They are generally indented for track use or off-road racing.
Emissions Non-Compliance: They produce a louder and more aggressive exhaust note.
The de-cat exhaust version is available for motorsport and off-road use exclusively worldwide.
