Hi Guys, ultimatley track width is depentant on wheel offset AND spacer width. Personally I prefer to widen the front about 15-20mm (overall) more than the back. So for most applications I would recommend 15mm spacers on the front (30mm overall) and 6mm on the back (12mm overall).
With my car the wheels are 37mm offset already so the backs without any spacers are around 10mm per wheel (20mm overall) wider than a stock MCS already. On the front which has our GTT /Porsche big brake kit (which gains 2mm per wheel) we then add GTT 6mm spacers. This means we gain 10mm from the wheel choice+ 2mm from the BB Kit + 6mm spacer= 18mm a wheel (36mm overall) wider than a stock car.
In summary Im circa 36mm wider than a typical MCS at the front & 20mm at the rear.
No wonder it handles so well.!
The front to back 'difference' I have is still less than a STANDARD Pug 205 1.9 GTi, they are about 32mm difference.
The Mini as standard is almost identical track width front & rear
We sell various length wheel bolts, please ring for prices (plenty in stock)