I LOVE this thing! it opens even if i only boost to 2 psi... no compressor surge EVER, and sounds great... It isnt loud, it sounds like air escaping. It gets louder the higher psi that you go. By FAR the BEST BOV I have ever used. I have used the SSQ the OLD school SSQ and the Plastic SQ (all HKS) If you need a BOV, buy this one.