71004-AF006 SUBARU Impreza WRX 2002-2004 2.0 Turbo 71004-AF008 SUBARU Impreza WRX 2005-2006 71004-AF006 SUBARU Impreza WRX STi 2002-2004 2.5 Turbo 71004-AF008 SUBARU Impreza WRX STi 2005-2006 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.