Audi S4/S5 B9 Non Sport Diff models - Resonated (Quieter) Cat-Back Exhaust System with Quad GT-90 Polished Trims Seat / Cupra > Ibiza > FR 1.8 20VT (Formula Racing) > 2004 to 2008 The default valve operating ranges

The default valve operating ranges will be lowered to allow for the valve to open sooner than the standard settings

Many exhaust manufacturers also advise these as a necessary upgrade when fitting a performance downpipe

the exhaust valve opens allowing exhaust gases to be split between the rear silencer and a rear silencer by-pass

- If you are unsure which type you need

Audi S4/S5 B9 Non Sport Diff models - Resonated (Quieter) Cat-Back Exhaust System with Quad GT-90 Polished Trims Seat / Cupra > Ibiza > FR 1.8 20VT (Formula Racing) > 2004 to 2008 The default valve operating rangesOur range of Cat Back systems are perfectly suited to cater for anyone looking to improve their sound and aesthetics, designed as a direct replacement for the original system, available in multiple configurations enabling the owner to choose the increase in volume of their exhaust and or add a more suitably aggressive tone. All our products are made from 304L Aircraft Grade stainless steel. This quality material will ensure that your Cat Back system