I dont think the 7's were made for ethanol content.. I'd be less worried about the tune aspect, and more about the ethanol content perishing rubber seals in our tanks, pumps, lines, injectors etc. They simply werent made for e10, assuming you are still running parts from 1990's. If everything has been swapped for modern rubber or something that can take it then it is probably ok.
As for the ecu tune, I can give my experience with conventional engines. Usually manufacturers in other countries that run high ethanol content (e85 flexfuel) supply the vehicles with different timing tables in the ecu (ignition advance) because of the ethanols burning properties (amongst lots of other things fuel related). Ethanol burns faster than regular fuel. It also takes more of it to burn at stoich (ethanol burns stoich at 9.7:1, pump fuel is 14.7:1). However as such small quantities of ethanol in the fuel with e10, unless youre on the bleeding edge of tune, I dont think it would make that much difference and would probably run fine.
A concern for me would be the effects of e10 and higher in the combustion chamber reacting with our lubricating oil. Does ethanol mean the oil injected into the chamber would have less of a lubricating effect? Does it break down or react with the oil somehow? This is something I have no idea about, but I know enough to say I wouldnt want to be the guinea pig. Perhaps I'm barking up the wrong tree with that one, just throwing ideas out there.
I'm sticking to V-power imo, enough goes wrong with my 7 already to be worried about that too
