I think 3 of the BIC subs are HSU clones.
Adam mentioned the $185 F12. It has the BASH 150W amp & 12" sub. The cabinet and overall aesthetics is less than the BIC H100.
The H100 is $220. It also has the 150W BASH amp & 12" sub, and the aesthetics is a lot nicer than the F12.
BoredSysAdmin mentioned the 3rd one - the $279 PL200, which has the same aesthetics as the H100, but a more powerful 250W BASH amp.
I think all three are decent for < $300 subs. but as shadyJ mentioned, any $600 subs from HSU, Epik, Rythmik, & Elemental Design will outperform any of these low-end subs for sure.
But what about subs in the $400-$500 range?
I don't think they will be any better than the 3 BIC/HSU clone subs. If you want a significant improvement, I believe you need to shell out $600.
BTW, I think I had the same Pioneer speakers when I was in college.

They did sound pretty good. I would just get a subwoofer.