@ glassaxe- E100 is a much cleaner burning fuel, but it has less energy per liter than gasoline. Ethanol engines can have much higher compression ratios because of this, allowing for more torque and horsepower and less of some emissions. There have been studies done by MIT that have produced ethanol fuel with octane ratings in the 130s.
As far as fuel economy goes, ethanol gets about 20-30% less fuel economy than gasoline. It is actually greater (around 50%), but with the increases in compression, economy increases. Comparably, ethanol produces about 0.5 kg/L less CO2 emissions than gasoline, but when the amount of energy per liter is taken into account gasoline becomes approximately 20% more efficient.
Gasoline is more efficient and has more energy per unit volume than ethanol, but ethanol allows for improved dynamics in a combustion motor. E100 will produce better performance than gasoline, but at the cost of efficiency and price.