check the pistons for what? unless its hit a valve the pistons wont show shit, what ya looking for is the rigde at the top of the bore, if its real bad the bores are very worn, or if you turn the engine over by hand look at the bore faces, any score etc then it needs a rebore.

i would check and change the cheapest stuff first,, but if your gunna do a bottom end rebuilt its gunna cost, you say might as well go zetec, thats up to you but if your think zvh they have there own problems to over come, skimming pistons, mod this, mod that etc i would stick with cvh unless you want to go the whole hog.

i priced up a 2.0l turbo lump to my FRST cvh, bear in mind i was doing it not a garage, and for the rebuild cost there wasnt much difference between the full zetec to the cvh, zetc worked out about £150 more give or take but then i had to allow for a live map tune, and there not cheap so bear that in mind, at least if you rebuild the cvh bottom end, and its done properly thats all you got to lay out for, and evey thing will fit back and theres no fucking about. modding engine mounts etc.

but the choice is yours, but cost wise for rebuilding cvh bottom end is gunna be (what ive paid just for my bottom end) £600-£650 thats everything, regrind, shell, pistons, rebor, gaskets, crank seals etc but on mainland where you are it shouls be a little cheaper, compaierd to the isle of wight