I wouldn't put an older G60 engine into a newer car, plus as Wayne has already pointed out, the G60 charger aint great.
If you was gonna do the 2.0l 8v, this lot would be a good start
Lower compression - about £200 for the head spacer
M62 Eaton Charger, M45 off the mini wont cope very well with the 2.0l engine £500 bare minimum
FMIC, pipework, brackets etc around the £300 mark minimum
After market engine management loom etc anything up to £800
Custom outlet manifold, downpipe, sports cat and full new exhaust £500 minimum
Bigger injectors £?? not cheap tho
So thats just off the top of my head and are only aproximates and comes to around £2500
Almost forgot, a worn 020 gearbox will probably only cope with about 160-170bhp so if you want more than that find a better box, more money

I would love to see this kind of build and have contemplated it myself many times but I aint got that sort of cash and even if I did.......................................................................
I probably wouldnt do it