Wheel spacers are used to move the wheel outward from the hub, either for a wider stance, or to get clearance for larger brakes.
The 3mm spacers are simply wafers that slot between your hub and wheel, and can be used with your factory wheel bolts.
The 5mm and larger spacers are a complete kit that includes hubcentric wheel spacers that maintain hub centricity for your wheels, plus a set of eight longer wheel bolts.
Each kit is a set of two wheel spacers.
Note that there are two different wheel bolt sizes for MINI. Before 2006 all MINI models used 12mm wheel bolts. After that the wheel bolts were 14mm. If you have a 2006 model, your best bet is to remove a wheel bolt and measure the diameter.
3mm Wheel Spacers
Includes two spacers.
$20.00
5mm Wheel Spacers
Includes two spacers and eight longer wheel bolts.
$89.00
15mm Wheel Spacers
Includes two 15mm wheel spacers and eight longer-than-stock wheel bolts.