I have this kit (15% pulley) and I'm very pleased with it.
The kit includes a very good puller (to remove your stock pulley), a belt (a bit smaller than the stock one) and a CD that contains the how-to and some cool MINI videos!
Installation was a breeze!
MINI Madness' website states that their pulleys are black for a "stealth" look but the one I received was polished... Not a big problem but they should update their website more often...
I've done more than 40 000Km with the 15% pulley and everything is going fine!
I would highly suggest an ECU remap to match the pulley. Running a pulley without it won't damage your engine (I did it for almost 40 000Km). I just installed MTH remap and the difference is great! It should come as a kit, MTH stage 1!