How much more difficult is it to installa complete 16v zetec opposed to a zvh?

I was thinking going down the zvh route because the head is retained which keeps things such as inlet / exhuast manifolds, but am starting to think about the 16v now, as I would want to have a reasonablly good head on the cvh (stage 2/3) which is gonna cost £xxx, whereas the zetec head as standard will be almost as good as a fully modded cvh, so there is money to be saved there.

Then there is the old saying of the zvh being a bodge, I just want to wiegh up how much more difficult a zetec install would be compared to the zvh.

Thanks!