You won't hit those numbers on a BK1 3.8T without building the block, beefing up the fuel system, and getting a good tune. Anything over 4 psi on a 6266 turbo on the BK1 and you're risking blowing the engine. That will give you somewhere in the range of 350-375whp. Build the block, heads, fuel system, supporting mods, etc. and you can get far in excess of that. Keep in mind that while a nitrous system may be cheaper, if you spray too low in the RPM range you run the same risks as running too much boost on a turbo kit.
2011 3.8T Track red
InstalledTurbonetics 6766 3.8T kit! Built engine, fuel return, flex fuel sensor, Haltech ECU, running E85, BTR custom tuned, currently working with Alphaspeed tuning, CNT exhaust, Vertini Racing wheels, Megan mounts, dual CCs, 1400cc injectors. Last dyno tune: 608whp/602wtq
ReceivedGarageline driveshaft couplers, solid diff bushings, PSM Pro coils, JRC rear diff cover, Sedan rear subframe, complete PSM suspension arms and super angle kit, Snow Perf. W/M kit