[jblackburn]

I don't seem to have any issues with it taking time to adjust. I'm guessing if you don't run your tank down low before filling up it will be diluted a prevent it from fully utilizing the 91 map.

Same - my '12 would adjust instantly.

I saw very little difference between 91 non-E and 93 10%. It was in the neighborhood of 1-2 MPG.