Down-firing subs and hardwood floors...

I have a Hsu VTF-2 that sits on my hardwood floor...it seems to sound good but it is my first sub so how would I know? Anyways...is this combo that horrible or could a piece of carpet underneath help a bit? If it is bad, any recommendations for a "non-downfiring" sub in the same price range?

If it sounds good why get a new one? Listen for a rattling or buzzing of the floor. If it doesn't exist you're fine and enjoy. Only you can answer that question.

Ok...so the hardwood floor shouldn't affect the "boominess" or rattling of windows/walls? I know rattling of windows is ok for some situations :) but if the hardwood doesn't affect that then I'm fine with it...