It's not worth it if you can buy 93 octane gas without enthanol.
I've noticed a 10% reduction in fuel mileage on my other cars using 10% ethanol vs. straight gas. Basically if they had added nothing and just gave me 10% less gas for the money, the results would have been similar.
If a station is selling 93 and 93 enthanol, go with the gas unless it is more than 15% more expensive than the ethanol. Ethanol shouldn't hurt the engine in the least, though.
Ethanol is boondoggle to help out farmers. period. It costs more energy to produce than it generates by burning. The sooner everyone realises this, the better.
I'm from Nebraska and respect the American farmer, but I have to call them like I see them.