Gas brands: does it matter?

[davester]

Markintosh wrote: Real world testing for 10% ethanol in gas results in more of a 6-10% drop in MPG.

Please provide a link to this real world testing. I looked and found nothing but results in the 3% range. To get a 6% drop in mileage the ethanol would have to have absorbed 50% water by volume, and as I noted earlier, to get to 10%, all the ethanol in E10 would have to have been replaced by water. That's just not reasonable.