Just bought the car. 87K, 95 E320 wagon. Stupid question, but the book calls for 91 octane or higher. Is this something I should adhere to? I burn 87 octane in everything else I own without problems. I don't think it actually makes all that much difference between 3.50 and 3.70 a gallon so I am happy to spend the difference if it is legitimate (paying 4.03 for dino diesel and 4.50 for biodiesel in the other MB right now so gas seems like steal). I'm never sure about some of these recommendations and the reasoning behind them. If legit then cool, fair enough and move on but I never know if say a board member of MB at the time also an Exxon board member!