From:
http://sr20det.nismo.org
"SR20DE vs. SR20DET (Remember 'T' is for Turbo)
Here are the differences between the DET and the DE:
The DET has oil squirter piston coolers The DET has a bigger oil pump. The DET has a different front pulley. The DET has lower compression pistons (8.3:1 vs 9.5:1). The DET has bigger injectors. The DET has direct ignition. The DET has a variable intake cam, runs retarded at idle, advanced mid range and retarded top end. The DET has mechanical shim in bucket type lifters with a slightly bigger in duration exhaust cam.
The GTi-R DET has individual Throttle body injection. The GTi-R DET has stronger main cap bolts. The GTi-R DET has beefier rods.
*Just about all parts between the SR20DET and the SR20DE are interchangeable. Comes in very handy!"
Just get the SR20DET since it comes with the transmission. The JDM Sr20DE is pretty crappy for the price it would cost since it didnt have too many changes from the USDM SR20DE I think the only thing it has is that variable lift thingymabob if you get it from an S14, S15 or another SR20DE equipped vehicle.