Mate in our Australian summer your car can run on 100% ethanol or 100% cheap ass 91, it has a flex fuel sensor and technical provisions so it can run on any combination of either in between and still maintain optimum tune.
Just sayin that nobody I have seen has actually reported on purely performance basis using 85% ethanol in the stock flex fuel tune.
So would be interesting to see how good / if you notice difference using higher octane in your LFX at WOT, part-mash-throttle, and decel. Yeah, real scientific like!
Empty the tank as much as possible before filling with e85, use United, and suspend your shock at 50% more fuel being consumed (up to 9.72 AFR).
Camaro forums are keen too btw, just tell it like it is with stock tune.