The theory that the R56's have more room for wider tires is a bit of a myth. There are slight dimensional differences, but it's not much. With the right offsets you won't rub as long as you don't lower it too much.
or hit any bumps, or put any weight in the back seat or the boot, or take turns too fast such that you compress the springs. From what I understand, the R56 simply has more room, not much more, but yes more room. The R56 however, has it's own issues like small wheel (i.e. 15") fitment due to the shape of the rear trailing arms, etc. Lowering the car can definitely make the tire move closer to rubbing in a static suspension condition. However, the stock springs are very compliant and so will allow much more suspension travel and possibly rubbing when those compliant springs are easily compressed. Case in point, I had rubbing in the back with my 215/45-17 RE01s on a 17 x7 wheel, et 45 and OEM sport suspension. I changed the springs to something slightly more firm and dropped the back about 7/8". It has never rubbed since. So, - the lowering made it worse - the added negative camber made it better - the stiffer springs made it better The bottom line is that it will be very very close and often you will have to make some adjustments elsewhere to get the fitment you want. Although not necessarily easy, the best thing to do is to try them on. A 235/40-17 is an awesome size for a MINI. If I was willing to trim some plastic and massage some metal this would be my street tire size. I am not saying don't do it, quite the contrary....please go get 'em and make 'em fit. Then let me try them on my car to see how painful it would be for me. With stock springs you may have luck with some lower control arms to allow you to introduce more negative camber. You just have to do it, and then start making your adjustments to make it fit.
Didnt read the whole thread, but IF you want to drive in any way performance oriented, or quietly (lol) avoid Vmaxx's. They give you that .5 finger gap and 2" of travel though!
Offset seems a bit on the high side and I'd worry about rubbing on the front strut. Is that a size dan has had luck with?
there may be a 5-8 mm spacer in your future. i don't think that there will be a big problem fitting most 235's. Hoosier 225/40/17's are wider than most other brands 235's. i ran them with a et40 and had no problems. if you dont consider the tire clearancing the wheel well liner a bit as a problem.