Hi folks. I seem to be getting some sort of vibration/rattle at around 2500/3000 revs, right as I'm coming onto boost. At 30mph I'm in 3rd gear, and thats when I hear it the most. It goes away with more revs.

I'm wondering if it's the baileys bov (I'm looking for an excuse to ditch this) or maybe something else. How can I go about diagnosing this? Any suggestions where to start?

I have an 04 WRX wagon with PPP, Baileys dump valve and K&N induction.