Audi TT Mk1 Big Turbo 3inch Down Pipe And De-cat Pipe For Garrett Turbochargers. 3 inch stainless steel down pipe assembly for All Garrett 5 bolt turbo exhaust housings. Down pipe has been ceramic coated to reduce temperatures. EGT sensor port and o2 sensor port locations. De-cat section with new flex joint and o2 sensor port.