Genuine HKS SSQV 4 Blow off Valve kit IMPREZA WRX STi GRB EJ207 2007/10 on
Will also suit NZ 2.5CC models 

SSQV4 is the lastest Blow Off Valve from HKS Japan and comes with everthing you need to install it . 

English instrcutions included 

HKS-71004-AF013 

HKS Super SQV (Super Sequential Blow Off Valve) uses a unique sequential valve structure and a differential pressure control system, which allows for a broad operation range from low boost to high boost. All vehicle specific Super SQV kits include both the HKS Triple Fin Sound insert and Recirculation insert