try NAD Auto. they have tons over japanese motors (USDM and JDM).

do not tune the vehicle yourself if you really dont know anything about boosted cars. Sell ur junk box sunfire b/c ive driven one, and they NO guts. If your going to boost your motor rebuild. It's going to cost some money but it'll be worth it. With a built bottom end you have some fun with the boost. Where as if you just throw a motor in there and slap on a turbo, your going to say "i'll keep it at 6psi" until one day you turn it up to 10+ and blow the motor.