Originally Posted by Chuck33079

Let's see, my guess would be upgrading:
Injectors/pump (maybe a fuel return system)
MAF piping
Heat exchanger or a custom air to air intercooler with new piping
All pullies/cogs
Meth injection
Appropriate exhaust to give you just the right amount of backpressure but not choke the motor

My gut feeling would be that it would be easier to sell the Stillen kit to someone who's ok with 400-450whp and buy a GTM stage 1.5 SC kit.