i just got a bigger top mount for my 04 WRX, so far i'm running full 3" turboback, ebc, intake, up pipe, headers, and soon to be stage2 with cobb ap, on stock turbo, i was just wondering about how much boost could i safely push? I'm currently pushing 15.

I would stick w/ 15 until you get a tune. Then I would ask the tuner what he would put it at. Or just get a bigger turbo and call it a day. I don't think by having a bigger IC that you should run more psi. The air going in the engine just may be cooler which helps. I could be wrong though...