Your songs have the maximum possible effect.
All variable, numeric effects of a song modified by this feat are maximized. Saving throws and opposed rolls are not affected, nor are songs without random variables. An empowered, maximized song gains the separate benefits of each feat: the maximum result plus half the normally rolled result.
MP Increase: +3 (a maximized song costs 3 additional MP more than the actual MP cost of the song.) In addition, the perform check DC increases by +3.