I'm looking for a subwoofer to add to my entry level 5.1 system. I have a Denon 2311ci receiver and a the Polk Audio RM95 5 speaker setup (which I am incredibly happy with). Now, some people have said in reviews that the RM95 is not that great when it comes to mid-range sound reproduction, but I have not noticed that in any way. Anyways, I'm looking at the SVS SB12-NSD ($550) and the Elemental Designs A5S-300 ($550). Both are sealed subs, have 12" woofers, and I would gladly have either one in my setup. The only real spec difference I can find is that the STA-400D amp in the SVS sub is a continuous 400 watt DSP, whereas the Elemental Designs LT.500 amp says 500 watts. Other than that, the Elemental Designs Sub is a little bigger and the SVS is a newer model. Any thoughts on which one I should go for? I am willing to spend $600 maximum on the subwoofer right now because I'm on a tight budget. Thanks!