subwoofer for B&W N802

I would like to add a sub to my 2 channel system. Does anyone know it the B&W ASW is a good match for the Nautilus line? Are their any B&W owners who can share their thoughts of adding a sub to these speakers?
I was using the B&W ASWN850 with my 802's. It sounded great and movies are so dynamic when called for. I would go for any of the 800 series of subwoofers if you could swing it, get the ones with individual phase, crossover, frequency, and volume settings. This will allow better integration with the speakers. Also consider the Velodyne SMS-1 subwoofer controller to extract the most of the subwoofer and help with room modes.