THe Ghis interior is easy, its a simple swap over. For what you describe youd be better to find someone wrecking a ghia and getting everything in one shot or it might be costly to get bits and peices here and there. Wiring in the trip computer is easy if you dont use the ghia wiring loom, power windows is easy but takes a bit more time and its fiddly getting the old regulators out. Putting the climate system in looks relativly easy in theory. I havent heard of anyone who has done it.
As fot the gas, Jase just converted his car to MPI and kept the old converter.
Dot Aye You