I assume you have not upgraded the stock air box to one of the cold-air intakes available? The stock airbox and resonator do an amazing job of silencing the turbo and BOV sounds. Unless your run the BOV in vent-to-atmosphere mode, you probably won't notice any change in sound with the stock airbox. Personally, I would recommend keeping the BOV in recirculation-mode for best engine performance.yea i installed my bov the hks one with the cpe flange that i got from the rpm store i installed it and everything works well but i have no sound??? any one know if i did something wrong or forgot something??
If you don't plan to switch to an aftermarket intake, you could try the "airbox mod" that involves removing the resonator and "tuba" if you want more sound.