If you want to absolutely maximize your ROI, original color is probably your best option. However, if "value" is less of the concern vs. owning a car you totally love, then I'd say go ahead and paint it whatever color floats your boat. As others have suggested though, if you are going to change the color, do it right and paint the ENTIRE car. Opening a hood and seeing a different color in the engine bay vs. the body is just no bueno.
On the topic of color and adding to what Trich wrote:
There is sort of a continuum here:
- Absolute purists would say you should keep the car silver if that's how it left the factory. And of course, not just "silver", but the exact paint code that Alfa used in 1969.
- The next step down from there would be to paint the car one of the other colors that was offered by Alfa Romeo in 1969. Sort of like transporting yourself back to an Alfa dealership in 1969 and choosing the color of your new car.
- Next step would be painting it a non-original color, but one available in 1969. Something single stage, non-metallic, not "wild". A color that Alfa didn't offer in 1969, but perhaps was offered on MG's, Mercedes, Peugeots, ... of that era.
- The last step down this slippery slope would be to paint it a modern color not available in 1969. Something like "a metallic blue with more of a silver undertone".
If you have any interest in showing your Alfa, a deviation beyond step #2
will cost you points.
I'm not in the camp that says doing anything beyond step #1
would be evil - my own Sprint corresponds to step #3
, so I certainly can't throw stones.