MILLTEK SSXAU673 Hi-Flow Sports Cat and Downpipe AUDI S4 3.0 Turbo V6 B9 - Saloon/Sedan&Avant (Non Sport Diff Cars)Description MILLTEK SSXAU673 Hi Flow Sports Cat and Downpipe AUDI S4 3. 0 Turbo V6 B9 Saloon Sedan&Avant (Non Sport Diff Cars) Milltek Sport Large Bore Downpipes are designed to improve both performance and sound. These downpipes feature a larger diameter compared to standard OEM parts, allowing more exhaust gas to exit the engine and pass through, which increases efficiency. When used with the Catalyst Bypass Pipe, significant power gains can be