The WRX Deceptor Pro blow-off valve is a 'bolt-on' fit for ALL Subaru WRX, STi, and ALL turbo Impreza variants manufactured during or after 2001 (models including and after the GDA, aka "bugeye").It doesn't require any adaptors, extras or modifications - just remove the factory BOV and bolt it on!The Deceptor Pro allows you to go from silent and stealthy to ear shattering in a matter of seconds whilst staying firmly put in your drivers seat!It is a little known fact that the late-model WRX factory blow-off valve is actually designed to leak at boost pressures exceeding the factory level. Replacing it noticeably improves throttle response, and is definitely recommended in applications where the boost has been raised.