Audi S4 B6/B7 - Catalyst Delete PipeThe part is used to bypass the catalyst from the exhaust to create a Decat system. Eliminating the catalyst will greatly enhance the gas flow and the performance, adding significant Hp to your vehicle by removing the density of the catalyst in which exhaust gases are pushed through. This product is intended for motorsport use only and requires Stage 2 ECU remap. All our performance exhaust systems are designed with you in mind, and we cater to an ever