Realistically it'll cost you at least a few grand if you do it properly. To buy and rebuild a 2L zetec, with a set of vauxhall pistons and all machine work, you're not looking at much less than £1500 (with new pumps, gaskets, uprated valve springs, etc). Then you've got turbo, manifolds, injectors, management, uprated fuel system, mapping, the list goes on..