Keep the GSR engine. It is the most bang for the buck you will find that fits into a DC2 chassis. A Type R engine is one of the worst choices for turbocharging because of the high compression. And that kind of mileage doesn't matter: I am boosting 8 psi on my stock motor with 133,000mi. As long as the compression and leakdown numbers are good, go for it. If not, rebuild that shit. You should be doing some major research about turbocharging because there is a lot more to them than what meets the eye.

Yeah, my GSR has amber corners, so the previous owner replaced them. What a shame....