This is a direct replacement recirculation valve that bolts directly to the turbo . It replaces the OEM diaphragm type valve with a piston design that allow for tuning with interchangable springs. For those running higher boost pressures after software tuning this really is a must to ensure that you do not lose boost through the valve. This valve is recommended for Volvo S40 and V40 1997-2004 (Mitsubishi TD04HL1-12T /14T) Renault Megane 225/230 Renault Megane RS 250 Hyundai Sonata Turbo 2011 onwards Kia Sportage and Optima