I agree w/ everyone on going with the m80, however, you might end up having to upgrade other components like the CC and/or possibly getting separates amps for the M80.
Since you already have a decent subwoofer, what I would do is try and build one of those Infinity Baffle rigs to handle the really low-freq hehehe… or to quench your upgradetis thirst you may buy one of this http://www.machinadynamica.com/machina41.htm (previously posted here)

The sailor does not pray for wind, he learns to sail. --Lindborg