Its cheaper than gas, but less creates less energy per gallon than gasoline so you'll be buying more e85. There are scientists stating that if we converted from gas to e85 the hole in the ozone will widen much quicker as the emissions may seem safer but are much more harmful to our ozone. The main reasons why racecars run on e85 is that it evaporates quickly and is safer for the drivers of said race cars if it catches on fire and is equivalent to about 105+ octane rating so they can up timing. Also the alcohol inside the e85 will eat rubber fuel lines, we did a test in science class to see what alcohol will disolve and rubber was one of them. Things you would really need to modify are, fuel pump (need more fuel to run at the same level), fuel filter, fuel lines, injectors, tune/ecu, and a larger gas tank if you want the same mileage out of a tank of fuel. I'm pretty sure I'm missing one other thing but I can't remember what it is.

Oh you also need a chip that you can switch back and forth between, I've heard of cars with a switch that you can flip if your using gas and you'll flip it again if your using e85 to adjust timing and a/f ratio and such.