best sub(s) for 800 u.s.

i'm looking for an amazing sub that goes really low and loud.a single sub or multiple subs.i also want quality sound and have a budget of 800.00 just for the woofer(s).i perfer a sealed box and the size does not matter, but open to ported.looking for something really impressive

any ideas or suggestions guys??
Personally, since budget doesn't really play into this, and since Ascendant's new line isn't available yet (as far as I know) you might as well stick with either a couple of Stryke Audio 15's or wait until Adire's new lines are readily available. 800 bucks would probably get you a top of the line Tumult 18 if you really want one. In any case, a pair a 15s would probably do you better, the Strykes are prettier and less expensive, but the Adires (depending on the line) will play lower and louder. I'd stick with sealed either way, just 'cuz that’s the way I am, but it depends on what you have to power this stuff.

If it were me, get a pair of Stryke 15s (if they're still available) and put the rest toward a decent power amp.
RE makes the XXX series subs which have a hefty 32mm one way excursion. They're XBL^2 also I believe. The only problem would be efficiency which is a whopping 91db for the 18" and only gets lower as cone area decreases. That and the "high" Fs that their subs have(from 25-30hz). Price, I cant even remember... less than $800 I hope