You have a great number of options in this price range if you buy used. Everything mentioned above has potential. You might also want to consider a pair of Marantz monoblocks for around $300 used. If you want to try Hafler, let me know. I have one that I was planning on listing shortly. Have fun with your search.
Stereo amplifier for a pair of passive subwoofers.
I want to drive the bass drivers on my speakers to reproduce the LFE from my Denon AVR-2805. I'm trying to find an used amplifier that can do the trick but I'm confused with so many model/brands and could not decide. Is there anything from the actual list under $400 that I can pick? Can a Hafler, B&K, Muse, Acurus, Parasound etc be a good pick? I will apreciate any help....