MTX 12" Thunder 6000 Subwoofers (SVC)
I bought two of these at a flea market for 100 total.
Overall, I would say they are a good mix of SQ and SPL. They sound pretty darn good at lower volumes, and get loud as **** if you want them to. Also I'm only running 200w rms over each of them, I don't see a reason to do anymore. I have them each in 1.25 ft^3 boxes with 3/4" MDF, no stuffing inside the boxes. Overall I'm happy with my purchase. For the price, they are hard to beat. It should be noted, these subs are not to be overpowered, they really aren't built to handle it.
I'm looking to buy some really nice components. 6.5" with 1" tweeters. PM me.