HELP: Subwoofer for music

I would like to get a subwoofer for music purposes. I don't really need earth rumbling low notes(I go to the movies for movies), but it would be nice to hear a low bass tone when one comes along. I bought the plans for the Decware WO32, horn loaded software, but there are so many variables that I am not sure I could build one correctly without building several until I got it right and I don't have the time and money, plus I think I will be hiring a skilled carpenter to build the thing for me(it will still be cheaper than buying it built from Decware). I found another set of subwoofer plans from BESL, www.bamberglab.com, and it looks promising(not as complex to build as the Decware WO32). The thing about the WO32 is that it is hard to find a subwoofer amp plate that will fit in the alloted space of the WO32 without taking it apart and I am no electrician, so who knows what can happen with that. I could just put binding post on the cabinet and use a solid state 100w amp that I am no longer using, but now I need a crossover....and....well....what a mess! The vandersteen(sp) looks like what I would like; 3 x 8in speakers, which would make it fast, but the price is out of this world for me, not to mention that you have to tune it for your system and what if I change my system?

Any suggestion would be great.