7.5 x 16 will be fine to fit onto a mini for the borbet a's.
the 8" wide borbet t's 14 inch may fit and once again the 7.5 x16's will fit ok.
If you are actually planning on fully euroing the car with coilovers etc be aware you may need spacers for the wider wheels as I have coilovers and 7.5 inch wide wheels and i required spacers.
I hope you stay on MINI2 as I want to see this car when it is done with the wheels and hopefully slammed!
EDIT: If you really are going to put 16x9 on the back be prepared for some mega stretch on those tyres to make it fit, i would recommend not going that wide on the back but spacing the wheels out.
Tell us your plans, im interested in the fact you are looking at these wheels as I want to euro my car next summer with smaller wheels and extreme lowerage, only for summer though lol Love my 18's too much
im currently in the process of doin this aswell.....borbet type A's and coilovers.... my problem is i want to buy both at the same time, wanna see how low i need to go to make it look schweet.... ive bought the borbets but obvioulsy both r pretty pricey....but i let us know how u get on n vice versa!!!