the ethanol is good in a way, as it cleans everything in the engine as it gets passed through. Its almost as good as having water injection except its in the fuel. However because its partially made up by ethanol the fuel isnt as dense and it also burns leaner, so when being tuned it needs to be richened up abit in comparison to normal fuel. By all means you should get a little less economy from a tank because of this. However it does have a higher octane rating, so it sort of works itself out. Think of it like methanol, it burns lean and cold, thats why you need to squirt 2.2 times as much over std fuel. But the octane rating of it is astronomical.
Thats how i see how the ethanol helps, whether its right or not is beyond me.