I want to add a powered subwoofer to use in conjunction with the factory speakers that come with the Pioneer 5020FD.
I may eventually get a receiver and go with a 5.1 or 7.1 system but then again, maybe not, and even if I do it probably won't be any time soon.
I just want something that will provide some nice tight, well controlled bass to supplement the factory speakers without overpowering them.
Any suggestions?

One place to look is the Dayton line at Parts Express.