Gas is ridiculous, and I'm not trying to spend a fortune here. I have a 1987 260E, the book/dash asks for premium fuel, but is that necessary. will regular do?. I know that the compression ratio and all that effect what fuel it takes but will it effect the car. the book says that if lower that premium fuel is used to not go above 2k rpms, but that gives me a top speed of 45 mph. while at the same time I don't want to spend money, I'm not trying to kill my car either