Why not just get a 1000/1 and run the subs off that?
I listend to that setup at a local shop and it sounded good at high volume. They didn't seem to do that great at say "normal" levels. But then you can adjust the gains to your liking.
I wasn't horribly impressed with the w6s. They're good subs, but I couldn't justify the price. It might be worth your while to go over to
www.caraudioforum.com and ask a few ?s and get some info on other types of subs.
When I was going to buy my 10w3v2s, it was suggested that I think about audiobahn alums, eclipese, and some other brands. I was actually going to try the Audiobahns, but I couldn't find a place to audition them at and the place online I was going to buy from was out of stock.
I really liked the eclipse subs, but they were a bit much for my wallet.
Also, get on google and search the newsgroups for info on your selection. When you're going to be spending this kind of $$$ it's never a bad idea to do a lot of research.
BTW, are you going for SPL or SQ?