Like you have said there are loads of guides for zetec conversions and i think most decent garages can do this conversion for you nowadays.

But as you have a low comp bottom end it might be worth changing you managment system before going zetec bottom end, with this you could go cossie management, gotech (fitted at jamsport) or megasquirt any of these three will give you a massive difference in performance as you can run larger injectors and more boost.