With a car as tiny as the 914, the risk is nearly entirely shouldered by the driver and his (presumably consenting) passengers. I had a 944 Turbo for a long time that had a number of similar... let's say eccentricities. Those unique qualities did not make it a danger to anyone else on the road--quite the opposite. When you sit in a car that old and bring it up just to highway speeds, it is abundantly clear that you are taking your life into your own hands.

Think about people who ride motorcycles, or small single-engine airplanes, or skydive. These are risky hobbies, and there usually isn't a practical reason for doing them. If something goes wrong, yes, passersby can potentially be harmed. Should we judge them harshly for these hobbies?