its most likely a pickup gap to big, or its snufing the spark out at the higher rpms. try br9eix ngk plugs and gap them down some. like 20 tho to 18 tho. what coil are you using you could also be overloading the pipes but i wouldnt look into that till you narrow out the other stuff.
the aftermarket stator COULD be causing it also.
tell shear turbo's dont work. 200+hp and 100ft lbs of tq?? hmm