slam lower frequencies of at least 20hz with little db loss (preferably 15hz but my budget isn't to high) (my current ones fully kick in at around 45hz) that can shake my room and get even louder than my current ones. My budget allows for the sub to be 2000$ max. Preferably I'd like them to be big (I know size doesn't matter but I like the look) and volume and a high frequency range is essential.
If you want to impress your mates at home. (Comes with condition).
Save up a little (maybe can get-by with $2000/-), DIY or get a box & put in TC Sound Ultra 5400 into it.
http://www.parts-express.com/tc-sounds-lms-ultra-5400-18-dvc-subwoofer--293-666Get a DSP amp to drive it.
This subject does produce deep bass (with box port tuning) for most low frequency from a movie & normal party music; but suck power like nothing if you want it louder. Home parties, movies will be awesome (You will be impressed, if its USED inside your home).
*Comparing to your existing 12" sealed sub.
Don't try bringing it out for backyard party... Unless you are talking about multiples of them (4/6 or many more) & lots of power.