How difficult is it to supercharge the mini one with either the cooper-s kit or works kit? Is it possible? What other parts would have to be changed (e.g. to 6 speed gearbox)? Would the cooper-s supercharger, intercooler and necessary bits be easy to get hold of? What price am I looking at? Sorry to bombard you all with questions, its just I want to be able to get the same performance figures as a well modified cooper-s e.g. around 250bhp mark eventually.
Any help in this subject would be great,
Cheers,
Nick.

Wouldn't be worth it. It'd be far cheaper to buy a Cooper S.

There's more to it than just a supercharger, it really would be a long way (and expensive way most likely) to do it.