Bob,
10% isn't so bad at sea level, but come up here and the story changes a bit. The fuel at the stations works generally OK for injected cars, whose systems are under vapor preventing pressure and whose fuel pumps are in the tank, where they'll stay relatively cool. By the way, that's the whole reason for that type installation. A hot external pump, near hot pavement, on a hot day, has one heck of a job to do to put thirty to forty pounds of pressure into an injection supply line. Vapor lock can actually happen at the entrance port to the pump. Ask anybody with a late eighties Jaguar about this deal, and then prepare for a dirty look...
No matter where you are, Alchohol in the fuel will degrade old low pressure type rubber fuel lines. This stuff just can't resist it. We ALWAYS install fuel injection grade hose where there is a choice, and we had to find this out the hard way. E85 will be a major undertaking for anyone with one of these classics.
Please don't mistake my intentions. I'm not just a curmudgeonly type campaigning against pollution reducing technology. Far from it, I embrace it wholeheartedly. What's annoying is that our cars, no matter how "dirty", are such a small niche that they do nothing to the overall picture, and we are also ignored by most major manufacturers when it comes to warning us about changes which threaten the condition of our automobiles. Witness the whole ZDDP thing. This cost my business, and therefore me personally, a bunch to rework engines we had rebuilt and whose cams and lifters went bad while the oil producing industry said NOTHING. They din't mind taking our money the whole time for the oil that was ruining our customers' engines, though.
Truly, we're on our own out here, and we need to look out for each other.
Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon