Not much guinea pigging going on, really. E10 is a fact of life in many areas, and I'm not all that far off of it. But I know what you mean- these vehicles are significant investments that we depend on for day to day life- not a good idea to play with too much fire. I know just enough about what I'm doing to be a threat to those around me

I would have been shocked if I did notice a problem. Even straight E85 shouldn't hurt in the short term (possibly not long term, either- lots of variables and not lots of outside studies on it). C-H bonds is C-H bonds- an ICE will burn 'em all, electronics and efficiencies notwithstanding.