If you are running more than E10 in a gasoline vehicle you are harming the planet. The engine control system is often not able to reach the ideal stoichiometric ratio with trim adjustments and will enter open loop. This will affect HC, CO and NOx emissions and catalyst efficiency will be reduced.
Save the planet. Run the right damn fuel in your car. If not, you have chosen to pollute our rivers and streams, kill polar bears and warm the globe!!!!!!
You are evil and should feel responsible for all the seemingly negative climate related events henceforth. You should register as a Republican and smoke a cigar with your rich, big oil corporate white collar cronies.
If it's flex fuel, yes I'm sure it feels a tad more peppy. Once the car realizes it is running ethanol it can apply a slightly more agressive ignition timing due to the detonation resistance of ethanol.