No dyno logs on my car. Didn't realize you already had the big turbo. Find a tuner and discuss your goals with them. The TunesPlus 400whp is designed to achieve 400whp so that is the parts list to get you there. Good luck.
400whp package from TunePlus is good. I went with the 350whp package with unlimited tunes. So E30 is an option down the road if I choose. The 350 package is the sweet spot on the $/hp curve.
Use it as a road map to guide your build...