MILLTEK SSXAU397 Cat-back Quad 100mm GT100 ECA AUDI S3 2.0 TFSI quattro 3-Door 8VDescription MILLTEK SSXAU397 Cat back Quad 100mm GT100 ECA AUDI S3 2. 0 TFSI quattro 3 Door 8V The Cat Back systems are designed to improve both sound and aesthetics, serving as a direct replacement for the original exhaust system. Multiple configurations are available, allowing the owner to select the desired increase in exhaust volume or achieve a more aggressive tone. Each system is manufactured from 304L aircraft grade stainless steel, ensuring