I live near the interstate and there are a few truck stops and they pretty much always compete with each other...however the Shell has 93 premium while the Pilot across the street only has 91 (and worse gas to begin with), so for the same price you might as well get the 93. I have found most of the Shell gas stations around me are all 93, and usually their 93 is the same price as the gas stations 91 across the street.HD926 said:What ever the highest octane is in your state is fine. I live in Kansas City Mo. and we have 91 and I have used it in Z28 -- a ZO6 corvette S2000 and so on and so on and as long as you use the highest you will be OK. You can find 92 at the old Amaco which is now BP. here. If 91 runs fine in a ZO6 this car will be fine.