EFI gains include, power, response, economy, and reliablilty so yes go EFI first!
IMO ZVH is a waste of time, either run a good CVH or go Zetec turbo, ZVH has all the bad points of a CVH engine, none of the good points of a Zetec, and requires big money spending on headwork, manifolds, and a big turbo to get a nice power band!
Almost any standalone management will be fine including Gotech, speak to whoever you will have map it and see what they recommend for best results