You more than likely aren't going to get anything too quality for 1000W at 500$. You'll probably want to look at the lower end subs. From what I've seen (haven't heard them) the Adire Shiva's are posted at 125$ on their site and I've only heard good things about them. Can't go wrong. www.adireaudio.com Glass or someone else might have a better choice in that price range.
Yea, depending if you were talking 500$ for SUBS or 500$ for sub/amp/enclosure. Two different stories. Subwise, IDMAXs, RE XXXs (or MTs for SPL) and the Adire Brahmas (Good step up from the Shivas), those are just great subs. Also running about 330$+ for a single sub.
how about around the rockford fosgate, jl..etc range..waht can u recomend for a lot of thump ..but still good sound quality??...somwhere around 1000watts maybe??