MILLTEK SSXAU295 Cat-back 100mm GT100 AUDI S4 4.2 V8 quattro B6 Saloon/Sedan Avant&CabrioletDescription MILLTEK SSXAU295 Cat back 100mm GT100 AUDI S4 4. 2 V8 quattro B6 Saloon Sedan Avant&Cabriolet The Cat Back systems are designed as direct replacements for the original exhaust, offering improved sound and aesthetics. Multiple configurations are available, allowing the owner to select the desired increase in exhaust volume and achieve a more aggressive tone if preferred. Manufactured from 304L aircraft grade stainless steel, these systems