Will a tune help my car out? I'm running 16psi boost from a stock turbo, with no cats, perrin intercooler and intake tubes, flowmaster muffler, perrin sways @ strut/tower braces, momo short ratchet shifter, K&N filter, ummm and i think thats about it... Just bought it, previous owner said it needed tuned so the boost could be turned up higher than 16psi... How much higher can we go with stock turbo? Will my car bennefit from a tune? I'd rather spend the 300 on a light bar and some lights, but if this tune will help and it will get rid of the CEL for no o2 sensor in catless downpipe, I'll do it. If its close.

its a 2002 suby wrx sedan