I'll be adding a FF tune to mine before anything else. I may stop there, I may not, but gaining 40whp and broadening the torque curve on nothing but an E85 tune is just too good to pass up.
I just saw this on Edmunds.com: "How much less isn't entirely clear. Adam Christian, Ford Performance's internal combustion technical expert, is non-committal in providing an exact number but hints that 15-20 hp is likely." I didn't realize it was that much. The Lund dyno numbers compare their tunes to the factory tune on 93 so the gains with FF are actually more than claimed if you take into account the 91 octane penalty.