Sorry I was less than clear. The manifold is not an issue for me. There is a difference between CIS-E and Digifant manifolds - the Digifant one has mounting bosses and tapped holes on the outside to enable mounting of the fuel rail and fuel pressure regulator. But I have plenty of those available. I just mentioned it as an example.

The one I am trying to decide what to do with is the coolant flanges. Early cars had aluminum ones, later cars had plastic ones. If I use the aluminum ones, I have a set modified to fit my gauges/sensor already. If I use the plastic ones I have to make adapters to make it all work. I guess there could be slight differences - plastic may be ounces lighter - aluminum may last longer (or vice versa).