ok so i checked with the old man about the claimed bhp on the supra and yes there were other mod's. the inlet compressor wheel was changed to increase forced induction.
my bad
looking to increase the bhp of the gto... try a remap of the ecu.
looking for greater bhp depends on how much you have too spend.
my old man has a supra twin turbo and he gain 150+ just with a good air flow system [induction kit] and cat back exhaust system with a remap...thats if you go to...