if it was me id be wanting a modern roller bearing billet turbo there will be a considerable increase in boost threshold, maybe a gtx3071 im sure there available on a cossie rear aswell, I got 2 gtx3071s on my car there great turbos will run 480 hp each and there restricted in mine aswell.


I found the rear housing for the gt30r and gt35r


http://www.atpturbo.com/mm5/merchant...&Category_Code=


that will bolt directly to your stock yb exhaust manifold so you can fit a modern turbo