On my '95 G20, I swapped in a JDM SR20 from Soken. Good guys.
http://www.sknengines.com/
If you get a FWD SR20DE-T, like Mike said, get the ECU and harness with it, and they MAY have a downpipe available. If not, hit up
www.brmexhaust.com, they have the SR turbo downpipe.
For the clutch, hit up RED_DET ^ for that... he knows high-hp FWD SR's like no one else.