methanol is a "refined" alcohol, unlike ethanol. it makes less btu's than gasoline, burns longer.
i dont think there are any disadvantages to using methanol other than the consumption and being harder to start in the cold. its cheaper than race fuel and it makes more torque. methanol is corrosive to aluminum and it attracts moisture, thats why you have to purge with gasoline. your internals will rust and corrode. also keep in a sealed container.
your carburetors will have to be set up for the extra amount of fuel that is required.
and the stuff is just plain awesome. lol