I'll add my current setup for the benefit of future engine builders.
Engine: Stock L28et (P90 head)
Turbo: Stage III T3/T04B .57 trim .63 a/r
Exhaust: 2.5†Scottie GNZ DP to 3†exhaust. Dynomaxx Muffler
IC: small NPR
Boost: 10psi I’m still tuning and this is mainly a street car so I need it to last. Eventually plan on running 15psi for the street. Boost starts at ~2500 rpm
ECU: SDS EM3-F (Magnecor wires, NGK BPR7ES plugs gapped at .030ish)
Injectors: Mercedes 420cc
HP: Did a quick dyno run on a Dynojet before my car was shipped from CA to FL. I had a igntion miss so I never got a clean run. I got only 1 run to about 5000rpm and netted 241hp 272 ft lbs. This was at ~10psi on CA 91 octane. I didn't log boost.
Overall I'm happy with this setup but of course I do have more mods planned.