I did not know, but tuners modify GT-R engines for E85, which is over 100 octane.
You might get over 100 octane, but alcohol does not have as much energy in it compared to gasoline.
http://en.wikipedia.org/wiki/Gasoline_gallon_equivalent
Pure ethanol (E100) has 66.67% of the energy that gasoline does. That’s why cars get crappier mileage with 10% ethanol in the gasoline than without it. That’s 1.5 gallons of ethanol to equal the energy of one gallon of gasoline.
E85 has 71.94%.
I can’t wait until we get away from ethanol in gasoline.