for supermike: You probably have 91 octane available. That is fine at your sea level altitude. Premium fuel varies in octane by altitude. Most deliveries of 93 octane are for higher altitude locations. In other words, 91 octane at sea level = 93 octane at say, Denver.

for all the rest of you: What is your problem? You bought a Benz and it likes premium fuel, so let the Big Dog drink. You can save a couple of dollars per fill-up and possibly pay a bigger price later.