The dizzy and AC compressor "improvements" I think actually would add a tiny bit of value than the OEM unless you're talking about a 100-point $200k show car.
Folks like to drive these cars; not be in museums.
These are somewhat simple bolt-ons/bolt-offs. Keep the originals in a box for safe-keeping, but I would much rather have these "improvements" if in a buying mode.
Now for stick shift cars, keeping the original trans would be okay, but I think a Getrag 265 conversion would ALSO add value.
The cars like to be driven and most of us enjoy driving them. Yet the act of doing that decreases "value" in monetary terms.
I'm sort of in the place of wanting to use the car to make memories as that's what is "value" to me. To do that it needs to work. That said, I have a 123 ignition, modern radio, the 14"ally wheels with hubcaps, LED bulbs, fittings for a tripmeter, immobiliser, extra 12v/USB supply on the tunnel, 3.46 diff and so forth. Would it win a concourse? hell no. Is it less valuable than it could be? Yes as it's used but I bought what a seller would call an "older restoration" (25 years old) in which MB Tex Cognac was swapped for Leather. Could it be "put back to original"? Easily at a cost but the monetary value is, I think, in a sorted, useable car as the "original" ship sailed a very long time ago: unlike Thelews car which is a timewarp original. Sticking anything on that which is not a simple bolt on/bolt off would be stupid and decrease value - in all it's definitions.
I am from the camp of "it's your car, do what you want with it" - so if that means wire wheels or a v8, good luck - not necessarily my thing but... The joy of this place is people know what left Sindelfingen and some folk have those cars or are recreating them. But that isn't for all of us. I've never driven another Pagoda so have no idea what "original" feels like.