Originally Posted by Midevil
Did you upgrade your stock BPV? They leak when you get around 17psi, so it may be that. The TMIC/BPV on the WRX are terrible and you will benefit by going aftermarket. The Forge BPV has had a lot of good reviews.
Iv read that sone people have carried the stock bov up to 22psi no problem. Can you explain why a struggling bov would make that noise though? Like what's physically causing the sound I make during boost?