MILLTEK SSXAU528 Cat-back Quad 100mm GT100 AUDI S3 2.0 TFSI quattro 3-Door 8VDescription MILLTEK SSXAU528 Cat back Quad 100mm GT100 AUDI S3 2. 0 TFSI quattro 3 Door 8V 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 or achieve a more aggressive tone. Each system is manufactured from 304L aircraft grade stainless steel, ensuring durability in harsh