If it were me, I would get the Outlaw LFM-1 Plus or the Hsu Research VTF2 mk3. Other good subs are the Elemental Designs A3-300 (there may be a bit of a wait on that one) and the Epik Legend looks like it might be a good sub too, when it comes out. You could get 2 Emotiva Ultra 10's also, in certain situations that would be a good setup.