AWE Tuning Audi S4 B7 4.2 V8 Exhaust Systems AWE Tuning Audi S4 B7 4.2 V8 Exhaust Systems Welcome to the finest catback exhaust for the B7 Audi S4 on the market. The AWE Tuning B7 S4 Performance Exhaust is a direct bolt on catback system that not only transforms the rear end of the car with it's... MSRP: Was: Now: £2,498.64 Choose Options