I did a experiment in my Ford Focus today had to drive a round trip of 1150 kms. I usually fill with regular with 10% ethanol as I did before I left. 2nd tank I filled with supreme without ethanol I increased my fuel mileage by 12 % without ethanol! The supreme coat me 3.00 more per tank but I got 76 kms more out of tank. So with the added mileage per tank I figured out the my savings per tank is 4.20 less the 3.00 is 1.20! Based on the amount of gas I use in a year I will save roughly 120 a year not that big a deal but can go 76 kms further and cheaper per tank! Plus I also drove harder with the supreme ...so probably would have been even better if I drove the same . This happened to anyone else?? Is 91 and higher octane for my car? I would put down calculations however I just drove 12 or so hours.