Perrin Performance Clutch Delay Valve Delete. Enhance your driving experience by installing the PERRIN Clutch Delay Valve Delete. 2006-2024 Subaru WRX. 2006-2021 Subaru STI. In aggressive driving scenarios such as fast shifts or launches, this can result in unwanted clutch slipping, causing premature wear on the clutch and reduced power transfer through the drivetrain.