Convert your ROUSH Quad Tip exhaust to a full Active exhaust and take control of your Exhaust note. Our Active Exhaust upgrade kit makes any 2015-2023 Active Ready quad-tip exhaust system into an active exhaust that allows you to tune your exhaust note using our iOS application for virtually infinite sound possibilities. The system utilizes an easily installed valve system that adjusts the flow of the exhaust, thereby adjusting tone and volume. Plug and play Installation requires no cutting or welding. Included in the kit is a 4 mode selector knob with faceplate so you easily switch to pre-set and custom modes on the fly.Converts the following ROUSH Active Ready Quad Tip Exhaust Systems to Full Active Exhaust Systems: 5.0L V8 Active Ready Exhaust Part #421921 2.3L I4 Active Ready Exhaust Part #421923