Audi S4 4.2 V8 quattro B6 Saloon/Sedan‚ Avant‚ & Cabriolet From 2003 To 2005 Cat Replacement Pipes - Milltek Sport

The 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.- For Track Use Only! - Manual Models Only - Must be fitted with the Milltek Sport cat-back system - Requires a Stage 2 ECU remap