Oil weight always has confused me. I can't make a good recommendation on that one. It depends upon the type of weather and temperature outside. Tom has used Mobil 1 Synthetic in all his cars because he has seen the actual valves in his car turn from light brown back to 'newish' looking after running the synthetic oil for a while.
I personally don't run synthetic very often in my cars, because they have been apart so much lately, that replacing the oil so often would bankrupt me. But normally, I would recommend the synthetic.
As for the gas type, I would run only high octane fuel in the car. These cars were designed for different fuels than are available today. I could go into a long explanation of why, but this is already answered on our site:
http://www.pelicanparts.com/914/914QA/914Q_engine_fuel_octane.htm
I think that this will answer your question.
Any other opinions?
-Wayne