A nice cosmetic upgrade for an early car is a Carrera 2/4 engine lid with retractable spoiler. The lid itself has the identical profile to the pre-90 version, but the hinges are spaced farther apart to clear the spoiler mechanism. Your best bet is to get the hinges when you get the engine lid.
Note the difference in hinge mounting points
I built a jig out of angle iron to match the C2 engine lid
bolt pattern. This made testing the hinge modification easier.
With the jig in place, you can really see the difference in mounting points.
I made small relief cuts with a body saw at the 90-degree portions of
the hinge, and then bent them by hand to fit the jig.
Here's a test-fit of the hinges on the car and the jig bolted up.
Then I welded up the relief cuts.
I wasn't able to get the hood shock to fit into the stock slot in the
new hinges, so I used a hitch pin and mounted it to the side.
The next step will be to wire in a load-sensing switch. The device
recommended is the AutoLoc Part # WC1000 "One Touch Up And Down Window Unit"
(schematic by Tyson Schmidt)