I would like to ask everyone's advice. There may be an old thread that covers this subject, but I couldn't find it. I am aware that the MM's recommended fuel is premium 91 octane. I have always gone to the local gas station which offers 93 octane with 10% ethanol. A new gas station has opened nearby which offers 91 octane with no ethanol.
Which one would be better for engine longevity for a daily driving, non-racing application? 93 octane with 10% ethanol or 91 octane non-ethanol? Does the ethanol make a difference? Positive or negative effects? I am not concerned about the price of the fuel, but rather the best fuel I can buy for my MM. Thank you in advance.