It may cost more to change to an auto, but considering the hassle of re-buying a car I wouldn't. I'm not sure which tranny you should get, but I'd look for one from a type R, or possibly, (some-one correct me if this is worng,) one from a true SIR. From what i remember reading somewhere the SIR has lower gear ratios, resulting in quicker accleration. It also has the factory LSD as well. The only downside I see to it is the whole fact of your milage will probably not be much different from your auto, and this tranny may take a whiel to lcoate.