With the influx of E15 at the pumps, what's everyone's feelings on running it in a stock or non-ethanol compatible fuel system? The EPA even says you shouldn't use it in cars older than 2001, but starting in May it appears it's coming if we like it or not. Is that enough ethanol to cause issues, like black goo, clogging, or seals degrading? I suppose this isn't just a DSM question, but in general any older car that wasn't designed for ethanol.

I'm also confused if the high grade 91+ octane will contain E15. From the sounds of it, yes, but I have yet to confirm. Anyone have any info here?

It's not an issue man. Just replace your fuel filter frequently for the first few months and you will be just fine. My old black 1G Talon ran on E85 in a bone stock fuel system car for a long time with no problems.

I've run a bunch of E30 93 Octane in my car when I travel out to my parents in Kansas because they have it at JumpStart gas stations out there and its always significantly cheaper than any other gas. The mileage drops by a few mpg but no issues other than that. Most all fuel has 10% already so 5% more isn't going to hurt anything but the fuel mileage. If you have always run ethanol free fuel then I would change your filter as stated above. The ethanol will not hurt anything but it has a tendency to clean things and all the goop ends up in your fuel filter and if you don't change it the filter can rupture and then it ends up in your injectors ask me how i know...