What is the displacement of your engine? Its a 1jz so its 2.5 litres right? Master power turbos are good turbos. I ran one of their T4 based T70s on my mustang for a while and had no problems with it. I run a ball bearing Turbonetics T-76 on it now. Hell i think a MP T-70 with the T4 and .68 a/r would work great on a 1jz.

I wouldn't put the GT45 on a supra unless it was really a drag only car. Rush has one on his car and to me its a little laggy. The turbine is 1.05 a/r and the turbine is pretty large for a smallish 2.5L-3.0L engine.