I've run what was labelled 10% ethanol blend in a 70's Saab with K-jetronic for about ten years with no undue problems whatsoever. It's been hard to find gasoline without ethanol around here (St. Louis) for about two decades.

The alarmists did claim that the introduction of even 10% ethanol would break accumulated stuff loose and plug the filters, but I didn't notice even that. I have had to change fuel filters, but none at an early age. I also had a fuel pump fail, but I'm guessing that it had run for well over 150K miles - the odometer had been broken on that car for at least five years before I got it.

Running 10% ethanol will slightly hurt your fuel milage, but it's hardly noticable. It certainly doesn't cut it by 10%. Maybe 2%. Add in reduced emissions which just might edge you by in a test, and it's a win.

I've also mixed 10% ethanol fuel with fuel that was not labelled as containing ethanol, presumably containing MTBE, and have never noticed a problem. Fill it up and drive.