Originally Posted by HuskerFocus
The power difference between the premium and regular (or regular plus) is negligible for the most part. In the long run premium will likely keep your engine cleaner (if you don't put in your own additives once in a while) and running more efficiently though.
Just stay away from E-85 (the engines even say nothing greater than E-10 should be used anyways). The difference between E-10 and Non-Ethanol gases is big from the energy point of view. I'll have to find the article (or crunch the numbers again), but even the $0.10 typical difference between E-10 and Non-Ethanol is such that you're better off paying for the Non-Ethanol fuels from a cost-benefit mpg point of view.
Only the Job 1 2012 cars say E0-E10, pretty much all the Job 2 2012 non PZEV cars (those built after 3/5/12) were Flex Fuel compatible and state for Gasoline or Ethanol fuel only, these are good for E0-E85 as evidenced by the blaze yellow fuel filler neck ring and warning documentation.
That doesn't mean you should run it, just that the car has been modified to tolerate it.