Originally Posted by Dracoheart
As far as I know anything FI from ford is 91 octane or higher, atleast that is how it was for the GT500, '03-'04 Cobra, and lightning.
The 1.6 Ecoboost and the 2.0 Ecoboost can both run on regular in other vehicles, so it is a possibility.
However, Ford has stated that premium DOES allow for the best performance (adds at least several ponies). So unless you had to pinch pennies, why not run premium.