My thought is that it really isn’t the octane rating that matters in our cars as much as the poor quality, inefficient additives (Ethanol, MTBE, etc.) that all the corrupt politicians have legislated into our fuel. 100% pure gasoline is higher in energy and more efficient than Gasohol (10% Ethanol) and E85 (85% Ethanol), resulting in increased engine power and MPG. Try searching
http://pure-gas.org for a gas station that sells Ethanol-free gas near you.