You are unequaled at the performance of one particular song.
Prerequisites: Perform 15 ranks, at least three metasong feats.
Pick one song which you have the ability to perform. Whenever you perform that song, you may apply any one metasong feat you have to that song without affecting its MP cost, as long as the total modified cost of the song does not exceed the maximum amount of MP you may spend on a single song. In addition, if you have other feats which allow you to apply a set numerical bonus to any aspect of this song (such as Spell Focus, Spell Penetration, and so on), double the bonus granted by that feat when applied to this song.