Short list of musical subwoofers

I plan to invest a "musical" subwoofer to augment the music listening experience of my current two-channel sound system. After a few digging over the acting forum and on-line reviews, it seems the following budgetary sealed (primarily) subwoofers are often mentioned and raved:

- Rythmic L12 (18Hz; sealed, servo controlled; 300 watts RMS; $609);

- RSL Speedwoofer 10S (24Hz; front ported; 350 watts; $428);

- Rel T5x (8 in; 32Hz@-6db; 125 watts; $680)

- SVS SB 1000 (24Hz, sealed; 300 watts; $450) or 2000 (19Hz; sealed; 500 watts; $600);

All above claim to have quick, accurate bass that is good for music listening. Rel, although not being able to extend to 20Hz, has been highly rated for easy integration into the sound system. I am not even sure if being able to get down low and/or the wattage of the active amp are critical to the musical application. My living room is about 25 ft wide and 20 ft deep. I do have limited budget but if others are warranted for a higher price tag in your opinion I am willing to bump up the budget. You inputs are highly appreciated.