If price is no option and you want ALOT of bass and still pretty good SQ then i would suggest DD 9912's or 9512's. They beat soo **** hard and can take sooo much.
There are also many many more that are amazing but i havent heard any of them so im not going to hate or hype them up. Good luck with your purchase though and make sure you give whatever you get enough power if your going with high end 12's.
How much power do you plan on running? How much space do you have? Are you actually doing SPL competitions, or just want a loud sub? If you are competing, which class and org?