if you are looking for rwd? the t9 gearbox from a sierra saphire 1.8cvh should bolt up to your zetec, you could probably use alot of those parts, axles, gearbox tunnel etc.not too sure how much abuse it will take before i was thinking of a similar conversion to my mk4 rs turbo.. you could still keep the engine non turbo and it would still be pretty quick. if you want turbo.. well i`d personally lower the cr myself, but there is so many options/opinions of tuning for the zetec. i`d like to see the progress if you find a way to do it
good luck with it