Gravity Performance decats instantly increase power by allowing exhaust gasses to exit the vehicle quicker. Our decats are designed to be direct replacements for the OEM catalytic converter, ensuring smooth installation every time. ---3" bore narrowing to 2.5" at the outlet for maximum exhaust flow ---Noticeably improves throttle response ---Free flowing to get the most from the 225bhp Bam engine ---Built in flexi joint helps reduce exhaust strain ---Sold for off-road / track use only Fitment ---Audi S3 8L 2001-2003 models ---Audi TT 8N (MK1) 1.8T 225bhp 1998-2006 models.