Unless you have a large budget, you are limited to more or less standard power (due to busting gearboxes etc) from a turbo a series

100bhp is pretty much the limit for an affordable mini that is reliable.

And you would be better off getting that with a 276cam, decent head, and rebuilt engine.


Far better to put a modern engine in.

Like a 500bhp turbo+nitrous 2.0 16v motor, that seems the sensible option to me