Any other regular (or irregular) posters bought the Ultra-X13? I'm in the market for a new sub and have been considering buying two, either stereo, or more likely, both connected to the Sub output of my 975. I've read lots of good comments regarding good large room coverage with 2 (or more) subs. I'm considering 2 Outlaw Ultra-X12's or 2 Rhythmik LVX12's or perhaps building 2 W-frame OB subs with servo amps. But, this Ultra-X13 just grabbed my attention.