I did a CAI mod on my r53 (K&N cone inside stock box, cut plastic bulkhead to feed into filter box extension). This mod also ditches the resonated front CAI feed. I'm hearing what sounds like a boost leak (on throttle only).

I checked my S/C horns because I did a bunch of work w/the s/c as well. I don't have a boost gauge and don't know if the OBD spits out a MAP signal.

For those of you running a similar setup, do you hear such leaky sound? It almost sounds like a blow off valve so am thinking it's the BPV i'm hearing actuate (I pushed it in and it springs back just fine).

The car also behaves a bit odd once I hit 3k rpm, as if there's a torque cut going on. Seems to recover just fine as I give it more throttle.