Audi RS4 (B7) - Valved Exhaust + MidPipesThe iconic CAPRISTO Valved Exhaust System offers the best of both worlds through its capability to produce an aggressive exhaust note under acceleration, and a more subdued sound for city driving. At lower engine speeds and during cruise operation the valves are closed and produce a deeper exhaust note. At wide open throttle the valves open, releasing the full symphony of the engine. The opening or closing of the CAPRISTO valves are controlled by the