Turbo XS Hybrid Blow Off Valve Type XS Subaru WRX 2015-2021 | W15-XS-HYB STI_2004-2007 If you are planning on

If you are planning on making 500whp or less

O2 sensor sold separately This item is non application specific

2005-2009 Subaru Outback XT

Fitment-compatible across A/R values within the same casting family

lighter solution where performance is critical or where space is a premium

Turbo XS Hybrid Blow Off Valve Type XS Subaru WRX 2015-2021 | W15-XS-HYB STI_2004-2007 If you are planning onFitment: Subaru WRX 2015 2021 Not too loud and not too quiet, the W15 XS HYB from TurboXS is the valve for you if you want an upgraded Blow Off Valve that you can hear when you want to but not when you don't. This valve is designed to vent partly to atmosphere and partly back to the intake giving you the "best of both worlds". This valve comes complete with everything you need to replace your stock bypass valve.