STxFoo, may i suggest Image Dynamics to you. I have been using their products for a couple of years now, and i can guarantee you will not find subs that reproduce better bass than them for their cost. Theyre tight and fast with bass.
Try out this link, the ID 8 D2 V.3 is your sub of choice.
Image Dynamics USA - Products - Idv.3
I have my IDMax 10" on the way for my new install. Earlier put two 12"s IDMax on a friends car powered by 1100watt monos on each... lets just say his car is friggin boomy.
Also check out their range of Q amplifiers, my first stock with the amps are arriving as they launched them recently, will give some feedback on that soon.