So does anybody know the facts behind this statement in the owner's manual?

Use only UNLEADED fuel or UNLEADED fuel blended with a maximum
of 10% ethanol. Do not use fuel ethanol (E85), diesel, methanol, leaded
fuel or any other fuel. The use of leaded fuel is prohibited by law and
could damage your vehicle.
Your vehicle was not designed to use fuel or fuel additives with metallic
compounds, including manganese-based additives.
Note: Use of any fuel other than those recommended may cause
powertrain damage, a loss of vehicle performance, and repairs may not
be covered under warranty.

thats bc you would be on the stock tune....

What's the average price for a gallon of E85 around here?

Who does a good E85 Tune around here?

E85 usually is about $0.60/gal cheaper, and typically hovers just under $3.00/gal.

Kevin Dunn (04sleeper) does a great job for e85 tunes, and tunes in general.

And stock injectors.

And rubber fuel lines, which Ethanol breaks down over time.

Very true. Its doesnt take long either. Still dont understand why ford didnt make these flex fuel which would have been awesome!

E85 NA isn't worth the time and money. Boosted is a different story.

Im not too sure the HP gains is worth the poor fuel economy . Nick did say not a hood idea for a daily though.

just talked to kevin all our fuel lines are metal except for one little rubber section running to the fuel rails...

The hp gains don't make it worth the fuel economy loss. If its just a weekender car then why not. But not on a daily in my opinion.

I agree wish ford made these cars flex fuel. Would make everything more interesting

I'm sure Ford will do something like that for the 2015 Mustang.

I agree with that BLK2012GT.

I run E85 on my boosted 3v and it's like magic gofast potion but n/a might not be worth it. Biggest problem with E85 is availability. I live near a Kroger that sells it but most Krogers don't sell it.

Some bad information in here. Just figure I would clear a few things up. E85 is perfectly fine with the stock lines. It will not degrade the small amount of rubber at all.

You WILL gain with E85. Even if it is only a few HP, the safety margin alone and not being on the verge of detonation is worth it IMO. It was the first mod I did to my car.

With these newer High Compression motors, high octane and good fuel is essential for longevity! Especially once tuned and pushing more timing than the factory has designed it for. E85 is a safeguard against detonation. No #8 failures here!