Itunes plugin recomendations?

Is there any plugins for iTunes that could help boost sound quality, like a bbe process plugin might? Also, if there are any other iTunes plugins that you like, please share!
yeah, but I download a lot of my music. And All of the cds I copy I do use error correction. What I'm looking for is something a little more along the lines of like what a sonic maximizer does. Thanks anyway though!