Sure, a new SVS or HSU would be nice but for $250 I would check your local Craigslist. That amount won't go very far on a brand new sub but in the used market you could find something pretty darn nice. I would look for Velodynes etc.. As an owner of a PSW505 I would say from personal experience that they really aren't that great when compared to the competition. I like Polk speakers I just feel their subs are kind of their week link.