Mini a series that brings back memories, I had a souped mini had a ex stud nicklaus sprint engine, stroked crank and relieved block for 1558cc I think it was, went like stink that was t3 on a cut down 45.
Anyway T3's could be described as old hat, wing to the vastly better from a lag point of view GT series with roller bearings.
I'd be cautious about using a turbo from a tdi, but if it would take the temp why go the whole hog and use a variable vane turbo as fitted to some tdi.
Why not efi it and use management be even better then ?
tabetha