Milltek Sport Large-Bore Downpipes are designed to improve both performance and sound. These downpipes feature a larger diameter compared to standard OEM parts, allowing more exhaust gas to exit the engine and pass through, which increases efficiency. When combined with the Hi-Flow Sports Cat, a significant increase in performance and a noticeable change in sound can be expected. This product is for fitment with the OE Cat-Back System only and requires a Stage 2 ECU remap. Note: Stage 2 ECU remap required. - Larger diameter than OEM for increased exhaust flow - Designed for use with OE Cat-Back System - Significant performance and sound improvement with Hi-Flow Sports Cat Specifications: - Pipe Diameter: 76.20 - Race Product: No - EMarked: No Kit comes with: - Large-bore Downpipe and 200-CPSI Hi-flow Sports Catalyst (EC-Approved) - MSAU623 - Connecting Pipe - MSAU673 Vehicle Compatibility: - Audi TT Mk3 TTS 2.0TFSI Quattro (Non-OPF/GPF Models) 2015-2018