Methanol is an oxygenate and raises octane but lowers power, since methanol has less power (BTU) per gallon than plain gas. Most any alcohol has less energy than gas. The octane boosters in a bottle are usually a waste, your better off going to a paint store and picking up some xylene or toluene and makeing your own octane booster. Both of these are over 110 octane and also have more BTU per gallon than gas. They are also safe for fuel systems, Cats, and O2 sensors, as long as you stay below a 20% mix.

Roll your own octane boosters:
http://www.vtr.org/maintain/gasoline-octane.html