Audi RS6 C8 Downpipes Catless and Catted: Performance, Sound & Emissions Guide

The Audi RS6 C8 is a masterpiece of German engineering — a luxurious wagon that delivers sports car-level performance. Powered by a 4.0-liter twin-turbo V8, the RS6 C8 is a favorite among enthusiasts who seek both practicality and track-ready power. One of the most popular performance upgrades for this vehicle is the installation of Audi RS6 C8 downpipes catless and catted, both of which dramatically enhance the car’s performance and sound characteristics.

What Are Downpipes and Why Upgrade Them?

Downpipes are a critical part of a vehicle’s exhaust system. They connect the turbochargers to the rest of the exhaust, channeling spent gases away from the engine. Stock downpipes often include restrictive catalytic converters that are designed primarily for emissions compliance rather than performance. By upgrading to aftermarket downpipes — either catted or catless — owners can significantly reduce backpressure, allowing for quicker turbo spool, improved throttle response, and increased horsepower.

Catless vs. Catted Downpipes: Key Differences

When choosing between catless and catted downpipes for the Audi RS6 C8, it’s important to understand the key differences:

• Catless Downpipes: These pipes eliminate the catalytic converters entirely, providing the least resistance to exhaust gases. The result is maximum performance gains, a louder and more aggressive exhaust note, and improved turbo response. However, they also come with downsides such as increased emissions, strong exhaust odors, and the possibility of triggering check engine lights due to the removal of the catalytic converter.
• Catted Downpipes: These include high-flow catalytic converters, which offer a balance between performance and emissions compliance. While they may not provide as much performance gain as catless options, they do reduce exhaust odor, help prevent CELs, and are more suitable for street use in areas with emissions regulations.

Both options are highly sought after by RS6 enthusiasts. For track use or in regions without strict emissions laws, catless downpipes may be ideal. For daily drivers or those in regulated regions, catted downpipes offer a more practical solution.

Performance Gains and Sound Enhancement

Upgrading to high-quality downpipes — whether catted or catless — can unlock significant horsepower. On a tuned Audi RS6 C8, owners often report gains of 25–40 horsepower simply from the downpipe upgrade alone. The turbochargers spool faster, and there’s a noticeable improvement in mid-range torque.

Sound is another major benefit. Catless downpipes provide a raw, aggressive exhaust note with deep burbles and pops on deceleration. Catted downpipes, while slightly more subdued, still deliver a more powerful and refined tone than stock.

Compatibility and Installation

Most aftermarket downpipes for the RS6 C8 are designed to be a direct fit, meaning minimal modifications are required. However, because the downpipes connect directly to the turbos and include tight clearances around sensitive components, professional installation is strongly recommended.

Many brands also offer compatible ECU tunes that are specifically designed to work with upgraded downpipes. This ensures optimal performance and helps manage any CELs that may result from sensor readings.

Legal Considerations

Before upgrading, it’s essential to be aware of local laws regarding emissions equipment. In many states or countries, removing or altering catalytic converters is illegal for street-driven vehicles. While catless downpipes offer unmatched performance, they are typically only recommended for off-road or track use. Catted downpipes, on the other hand, may be legal depending on the catalytic converter’s efficiency rating and your jurisdiction’s emission laws.

Final Thoughts

For Audi RS6 C8 owners looking to take their performance to the next level, upgrading to aftermarket downpipes is one of the most effective modifications available. Whether you choose catless for maximum output or catted for a balanced solution, you’ll enjoy a more responsive engine, an enhanced exhaust note, and a more thrilling driving experience. Be sure to pair your downpipes with proper tuning and consult your local regulations to ensure you’re in compliance.