This system replaces the primary OEM catalyst with a Hi-Flow Sports catalyst. The lower density of the sport catalyst allows exhaust gases to be less restricted and pass through more effectively. The sports catalyst is equipped with a Turbo elbow, providing an improved connection to the vehicles turbo. The wide diameter of the outlet allows the turbo to spool sooner, increasing performance and improving throttle response. Note: Requires Stage 2 ECU Remap. - Replaces the primary OEM catalyst with a Hi-Flow Sports catalyst - Turbo elbow included for improved turbo connection - Wide diameter outlet enables earlier turbo spool and better throttle response Specifications: - Pipe Diameter: 76.20 - Race Product: Yes - EMarked: No Kit comes with: - 100mm Hi-Flow Turbo Elbow - MSAU679 - High Flow 200cpsi Cat Assembly - MSAU680 Vehicle Compatibility: - Audi RS3 Sportback (8V MQB - Pre Facelift Only) 2015-2017