If you're running stock boost, then why do you want to upgrade the turbo? Raise the boost, and tune the car. You should be more then happy. There is no need at all to upgrade your turbo at this point. Your car is probably making just over 200whp @9psi. You need to raise the boost, get larger injectors, and some engine managment. Once you get that all done I bet you will be seeing low 300's.