Quote Originally Posted by BoiseAudi View Post
Don't mean to hijack however if Injectors and Turbos are the issue with getting past 550hp range what is stopping people from replacing those? What else is required to do that?
For 550+ you gonna need injectors, possibly fuel pump and intercoolers.
For 580+ add hybrid turbos or stiffer wastegate springs at the very least.
For 650+ you gonna need custom full-frame turbos and custom manifolds ($$$). I know a couple of guys who are experimenting with getting GT28RS's in there with stock manifolds, but no real results for now.
Bigger MAP, MAFs, DVs, stronger gearbox, etc.
Highly modded software is needed for any non-stock turbo, if you intend to run past 1.5 bar of boost.
Add WMI kit to any "stage" for safety. Won't get much extra power out of it due to being limited by turbos mostly, though.

Stock internals are good for at least ~1.8 peak.