The good news is that subwoofers, when operating in linear range, sound alike. It doesn't matter whether its a $200 BIC or a $20,000 Wilson Audio sub. The way with which its interacting with the air is the same. Most manufacturers will disagree with me, as it goes against their sales pitch, but subs are relatively simple acoustic devices as compared to full or wide-range loudspeakers. Brands don't matter, only linear and non-linear distortion matters. This is the next big audio myth that needs to die, and so many people, even those who pride themselves on being 'objective' in audio, still cling on to it.