From what I've read on the internals they're all forged. Which should mean a pretty hardy power output on the stock bottom end. Honestly, your real issue will be heat output. I'm pretty confident 500-525HP could be done reliably if you upgrade the intercooler and radiator. I really don't know how much the stock components could really handle heat wise. But if you're just doing exhaust and intake that'll be a non-factor really. The real issue will come with chip tunes increasing boost output and if the intercooler and radiator can keep up with the heat output. It's one of those yet to be seen sort of things. But I don't see a 2-3PSI boost really hurting to much unless you're hard on the motor.
Most of what I'm saying is really all an educated guess. As the old saying goes, you pay to play.
