Armen, I recently purchased an SVS PC13-Ultra and it blends very well with my M22s in a much larger room than you have. I don't play at earsplitting levels; and I'm crossed over at 80Hz so the M22s dishes out all I want to handle.
I've thought about getting M60s so I can cross over the sub at 50Hz; but I'm not sure the M60s will handle the 50-80Hz range any better than the PC13-Ultra will. When you buy a high end sub it should not only go deep, but should also reach higher with good linearity.
By the way the Axiom EP-600 is a very good competitor to the SVS PB-13 Ultra and has a longer warrentee. If I had considered the PB13-Ultra instead of the PC13-Ultra it would have been a tough decision. Both companies have excellant return policies and customer service. Form factor is very different on those two subs and the EP-600 can be purchased in vertical or horizontal orientations so take a close look at it.
Bill
