If it's about keeping the car original, buy one that came with it from the factory. If it's about making more power, get newer, more common and more reliable components.
A car with a Kugelfischer would be the bane of my existence
Before I bought the spider last year, I test drove an alfa with mechanical injection. I thought hmmm how bad could it be? Then I did research on it and when the seller said "Yeah, sometimes it starts a little rough cold, the valve needs to be replaced" I was like "nope!".