to be fair mate it totally down to how much you wanna spend and if your goin to do the work yourself
pumaspeed would charge around 3-4 grand to install a puma lump in a zetec s yet my mate bought an insurance write off puma for 150 quid took the lump gearbox wiring and mount , plus the alloys ,brakes and other silly little bits and scraped the shell for 80 quid , then sold his zetec s engine off for 150 quid ,so he ended up making money .
if money is no object stick a mark 1 focus rs lump in there then it would be a flyer!!