I've seen the effects of watered down gas broken down on the side of the highway.
There was a station near where I used to live that I swore had better gas than the big names (well, it was cheaper anyway). Now I just price shop and I haven't really noticed a difference. The gas log helps to quantify things like that.
I wish I could get non-ethanol gas around here, but I'm fairly certain it's a state requirement
*edit* -
yup
Welcome pauldelaitre! My fiance is part French, along with part Irish, Italian, Czech...