Audi TTS MK3 Non GPF models - Stainless Steel Cast Downpipe with Race Cat (For Milltek Cat-Back)For Fitment with the OE Exhaust system only Requires a Stage 2 ECU remap Our range of Cast Downpipes offer further enhancements to gas flow and heat management, being designed to increase efficiency and performance gains. Standard OEM catalysts are usually round 500 600 cells, our race catalyst reduces this to 200 cells. This makes the catalyst freer flowing, improving gas flow and performance. All our performance exhaust systems are designed with you