Recomend Sub for Paradigm Millenia 20's

[drummerboy_2002]

About a year ago I upgraded my front 3 to the 20's. Now it's time to upgrade my old sub. There are so many sub companies out there, I don't really know where to start looking.

Needs:
- Flat responce from 20 to 120 hz.
- Auto on/off
- LFE input
- Phase control

Wants:
- Small footprint (this can be due to cube sub, or tube sub [WAF])
- Style to match gloss black 20's.

Room Diamentions:
- L shaped livingroom (18w16d12h)/entry (8w6d12h) [aproximations]
- Openings to hall, kitchen and dining room.

Notes:
While I mostly watch movies and play games, I tend toward a musical preference from my sound. In other words, I prefer accuracy over power. Also, I'd like to keep this under $500, but I've learned from my last outting that my budget is more of a suggestion than a requirement.

Thanks to any and all with a suggestion.