to help this forum get on the right track
here's your answer to what's available in japan
http://www.mitsubishi-motors.co.jp/docs8/productss/gto99/lineup.html
GTO Twin Turbo(AWD, AWS, ECS, TT)
GTO Twin TurboMR(AWD, TT, sports suspension)
GTO SR(AWD, NA)
in the U.S.
we have the VR-4/Stealth RT-TT(which have the same as the regular GTO Twin Turbo)
and the base model and SL.
91-93 VR-4's had 300hp(9psi)
94+ VR-4's had 320hp(11psi)
depending which years you get the base model will have the identical amount of HP as the SL, which is 222hp. and other years... you will get stuck with 160hp.