As anecdotal as it is, my car gets about 2MPG better when I use the No-E No-Name stations around Greenville. Can't break 27mpg on the highway otherwise in a 328i, even at 70 with the Georgia staties hiding in the bushes.

Maine had a legislation a few years ago to ban ethanol from Premium gas, but I guess Irving (the Canadians) got past that. I miss that Super 102 in Germany, even if it cost 1.69 per liter. Das machte schnell.