A couple of things...
The Paradigm DSP series are ported subs. They have dual ports in the baffle, directly below the driver.
Paradigm's new SE series sub is their ultra-compact category sub. It has a 10" downward (or forward!) facing driver, in a sealed cabinet with only an 11" footprint. Tune the sub with the Perfect Bass Kit and you have an extremely linear, articulate, ultra-compact sub with low-bass extension that I dare to label "shocking" for the cabinet's tiny dimensions. I know firsthand, I use one in my bedroom.
I do like the inclusion of the subsonic filter the SVS sub has... With those four little upward firing ports (with a metal grill sitting on top no less...), I can almost hear the chuffing from here! I'm sure it would be helpful to filter out all that information below the tuning frequency with the SVS.