Heck, screw the 2JZ, put a SBC in there, auto trans, and it's EASY to make it into a decient car power wise. (Besides, the auto is easy to figure out as shift linkage is a cable...)
Wrecked F body.
Get engine/ecu and trans, and other parts you might want like engine/trans mounts for modification...
Measure, and install.
A "turbo" body older Z car with a 375hp V8 would be fun. I don't think the bodies were built as well as the Supra, and the interiors are shit compared to the Supra, but hey, it's a lighter car IIRC.
A MK2 Supra with a V8 conversion would be a better car IMHO.