I run E85 in "regular" vehicles with no mods.
Caveats:
Don't run straight E85 in subfreezing weather. My Fords do well on straight E85 in the summer. So I run blends in spring and fall; the strength varies with outside temps. If the mix is too heavy with E85 for the temp it may start hard and run poorly until the engine warms up.
Special circumstance: I did a long road trip recently in subfreezing temps and I ran a strong E85 mix, but that is because the car was already warmed up and I knew I'd be topping off with regular gas at or near my destination before shutting it off. Saved 60 cents a gallon for that segment!
