Ethanol can be used as a poor mans race fuel. Thes require a rejet and possible oil mixture change. I always run 32:1 because I'm paranoid - (i normally run yamalube 2r)
E85 - 105 Octane
E85 burns cleaner can offer more horsepower and is cheaper. Downsides are these; You need richer jets, it doesn't lubricate as well as pure gasoline, so more oil may be needed, it requires higher compression/advanced timing to see the real benefits.
Flex fuel vehicles that can run e85 are not optimized for ethanol, so they actually suffer power or gasoline.
Today, in Wichita KS, 91octane is $3.72 a gallon, ethonal is confirmed at $3.39, but internet says there is a station selling it as cheap as $2.29 here in town(im going to check this out soon).