You can do ALOT with the FWD sr20. You can keep the SR20 and buy a turbo manifold/turbo from a Bluebird SR20DET or a Pulsar GTi-R SR20DET. There are tons of aftermarket turbo kits for the SR20DE. My 4 door Sentra with the GTi-R SR20DET ran a 12.836 @ 112.98 mph on a stock motor.

Its a excellent motor with tons of aftermarket support.