Ethanol has been mandated on all car gas for a few years now in North America. All gas companies need to have an average of 15 to 20% ethanol in their gas depending in which state or province you live in. If you want ethanol free gas you will need to go to a local small airport, as they are exempt form the ethanol scam for safety reasons. The ethanol increases the chance of carburetor icing at higher altitude in piston engine airplanes. You can get 87 grade Aviation Gas at all local airports.

Some gas stations have no ethanol in the high grade gas as they mix more ethanol in the lower grades to get their mandated percentages, but higher octane levels will make our small engines really hard to start and run poorly. All gas grade 87, 89, 93 have the same number of calories to burn and therefore all have the same power output. Higher grade gas is used on high compression engines. The higher the compression the higher the power output of any piston engine.

Octane is used in higher compression engines to control pre-mature ignition / knock. Our small engines have approx. 7.5 to 1 compression ratio and start and run best with regular 87-octane gas. Running higher grades will not give you more power and will make it harder to start, as the octane changes the flash point of gasoline and will not ignite as readily as with 87 grade gas.

Bound_4_Hell
You can never have enough power, as you can always throttle back.