Originally Posted by freetors
As preciously mentioned by one of the other posters, many of the auto tuning shops have taken to a liking E85. This is predominantly because of they typically work on forced induction cars that require higher octanes than normal gas in order to increase the boost safely. Race gas is very expensive so their defacto choice is to use E85 which has a similar octane rating but costs much less. To use E85 and make more power requires big injectors, big fuel pumps, and big boost to take advantage of that pesky 9:1 stoich ratio. Unfortunately this also gives abysmal gas mileage, often times getting 2/3 or less mpg for similar power levels with straight gas.
Also has the added benefit of lower burning temp, which is handy when are heating the intake charge to hell and back with a giant spool. Turbo guys LOVE E86, and they are using gigantic injecters to dump enough of it to keep up.
Great for dyno runs and show cars, not sure I would want to drive like that day to day, talk about passing everything but the gas station.