Good to hear it has finally arrived.
It is still possible to fit 12" wheels over metro turbo / era brakes as a friend of mine has done this before.
http://www.eraturbo.com/technical/page1/h02.png
this is a link to the microfiche page for the brake set up you should have.
the brakes should be 8.4" twin vented discs with 4 pot callipurs and you should easily be able to tell it they are correct by removing one of the front wheels and taking a look. the drive flanges should also have 4 raised pieces around the hub nut. these may have been ground off to fit the 12" wheels, but this shouldn't cause you any problems if they have.
With regard to the wheels, originals do come up occasionally on ebay, however some people list wheels as era wheels and they might not be.
sometimes they are revolution 5 spoke rfx, and sometimes they are ones produced by rover in the last few years of mini manufacture.
If you cant get originals, the rover ones are the next best thing, followed by the rfx's.
The wheels are 13"x6", but i am not sure what the offset is. i have 1 genuine & 1 rover one in the shed, i could measure them if you want.
the rover ones are not quite as far spaced from the hub as the genuine ones, but they do fit ok (about 1/2" closer to the shocks).
the tyres used were 165x60x13, i think they were dunlops, but i believe they are hard to find. i have used 175x55x13 on mine, but the o/a diameter is too small really, and my speedo is off too.
http://www.falkentyres.co.uk/prodtype.a ... istory=cat
here are some alternatives. click on 13" in the list, £33 each.
With regard to the ones on ebay, i would suggest not. my car is a replica that took me ages to find the parts for. I was intending to use the tyres from the metro turbo donor car, but on the metro rims the 185x55x13's would not clear the rear radius arm outer brackets.
i am also not sure about the stud patten too because these came from a K series metro.
i hope this helps.
regards
Darren.
ps will you be looking for a place on the stand at mitp?
. I think it would look more original if it had the RFX wheels but i would really like to know the offset to be sure they will fit. Could you please check on the inside of the wheel for me when you get a chance.