i had the same discussion with sum guys that have been owning a supra for years in chicago,, i askd them if its possible and yes they did tell me its possible but

like everybody has told u already u have to f*** wit the firewall and the harness,, so ur left with two choices then,, the 1jz or the 7mgte

the perks of a 1jz is it can handle more abuse but not that much and its so hard looking for parts, not to mention more expensive, plus dont get a jdm engine ,, its more headache than its worth jus look for a 7mgte and replace with a metal head gasket , and youll be good to go all you need is the stock manual transmission from another turbo