KDub,
I have a sunfire mkii sub and two supercube reference subs, close but not exactly what you're comparing. But my front speakers are def tech 7001's which have a supercube one in each speaker (drivers and amps anyway) and i will say that while the ones don't have the extension of the references, they are faster and tighter for music. The sunfire is a great little sub, very tactile, and its small size makes it easy to place behind a chair or loveseat. In april i hope to upgrade the sunfire to a def tech trinity sub, so it'll be on the market!