This product is designed for fitment with the OE exhaust system only and requires a Stage 2 ECU remap. The range of cast downpipes offers enhancements to gas-flow and heat management, aiming to increase efficiency and performance gains. The standard OEM catalysts are typically around 500-600 cells, while the race catalyst reduces this to 200 cells. This results in a freer-flowing catalyst, improving gas-flow and overall performance. Note: Requires a Stage 2 ECU remap. - Designed for use with the OE exhaust system only - Cast downpipe with 200 cell race catalyst for improved gas-flow - Enhances heat management and efficiency - Made in the UK and distributed to over 90 countries Specifications: - Pipe Diameter: 76.20 - Race Product: Yes - EMarked: No Kit comes with: - MSAU673: Connecting Pipe - MSVAG06NC: Cast Downpipe with 200CPSI No Cell Race Cat Vehicle Compatibility: - 2015-2018 Audi TT Mk3 TTS 2.0TFSI Quattro (Non-OPF/GPF Models)