The all new B9 Audi S4 & S5 is an impressive beast off the factory floor. Even the OEM exhaust tone isn't bad for a stock car. But if you are like us you want to hear your S4/S5 roar. Welcome the IE downpipe for the Audi B9 S4 and S5 applications.

Every detail is maximized to provide the turbo and engine with a completely unrestricted exhaust flow path for up to 45HP & 41TQ (on hybrid turbo setup). The TIG-welded 304 stainless and investment cast body delivers addictive sound, quality finish, effortless install, reliability, and maximized performance for your turbocharged V6.

IE's unique thick-wall investment castings produce an aggressive, drone-free exhaust note without the "tinny" sound typical on most full stainless body aftermarket options. Enjoy not only a louder exhaust but one with improved engine and turbo notes that will deliver miles of smiles.

Investment Casting

Other aftermarket downpipes use large sections of thin-wall steel tubing to manufacture the downpipe body; this is a cheaper process but can reduce sound quality and sacrifice exhaust flow. Investment casting allows for an optimized design that smoothly transitions exhaust flow from the massive 6" body to the dual 2.5" exhaust legs. The casting also provides a beautiful look that turns the entire downpipe into an attractive gold finish as it wears in from heat cycles over time.

200 CPSI Catalytic Converter

IE's downpipe includes a high-flow 200 CPSI catalytic converter. This performance CAT allows for full and unrestricted power from Stage 2 ECU tunes and hybrid turbo upgrades while reducing emissions output and eliminating unwanted smells and bumper stains found on cat-less designs.

Hybrid Turbo Ready

The stock downpipe becomes a significant restriction when upgrading to a larger hybrid turbo. IE's cast downpipe is a direct-fit to available upgraded turbochargers on the market and will allow total horsepower, torque, and spool potential from your turbocharger investment.

Dyno Gains Chart

The following chart details the power gains (WHP & WTQ) over the baseline power numbers taken from the stock downpipe on our hybrid turbo development S4. The "0" baseline is the maximum power/torque made, and each following increment is the additional power gained from the IE downpipe upgrade.

Note: Requires Stage 2 or hybrid turbo ECU tuning