Euro 280SE Octane Requirements
 

Just bought a 1979 280SE which was imported from Germany. The owner's manual is in German and all I learned in school was French and Latin which doesn't help too much.

As far as I can tell the specific engine model on this car is M100.985. To err on the safe side, I've been filling it with Premium gasoline, but would like to know from the forum what the recommended grade of gasoline is for this engine.