Let's not try to reinvent the wheel here. I do believe a stock turbo with E30 tuning is topped out at 230whp. So if you want to go more in terms of HP, a hybrid or bigger turbo is the next step. If you are not familiar with the differences between a Big turbo and a hybrid are. Hybrids spin up fast like a stock turbo, and makes quite a bit more HP on top. Big turbos are slower to spool up , but the HP just keeps building, way past what a hybrid can do.
So, you have to figure out what your goals are, if 230ish whp is fine, then upgrade the FMIC, maybe the intake and exhaust, find a tuner and get a E30 tune. More HP with gobs of bottom end torque, then a hybrid. If you want massive top end, go bigger turbo. Sky's the limit, but you gotta pay to play.
I have a hybrid, it's putting out lower 280 whp with an E30 tune. I've hit the limits of the stock fuel system. I can get a bit more by going aux fuel, how much more I can safely get, without big sacrifices in longevity, we will find out once my aux fuel setup is installed.