Depends on the F/A ratio. Both methanol and ethanol will give more power than gasoline, even though gasoline has more chemical energy than either one, but that's simply because you can run alcohol with a much richer mixture. Alcohols will burn over a wide range of F/A ratios, whereas gasoline ignition is limited to a comparatively small range. So, an alcohol car can give excellent fuel mileage...and barely have the power to get out of its own way...or excellent performance...and barely make it from one fueling station to the next...depending upon the F/A ratio. That's why you have to be careful when examining the claims made by those who "push" alcohol fuels for street use.
Forced induction is independent of the F/A ratio, so the percentage increase will remain the same. (The cooling effect of a rich alcohol mixture allows higher boost pressures, however, so forced induction on an alcohol engine might appear to yield superior results.)