True, the Shiva is not discontinued. Also true that Don has installed at least a couple. Best sub I have available for under $200 is the 12 inch MacDaddy in my living room. But if you want tons of bass I would get at least two. One is loud, but not going to rattle the windows of the car three lanes over on the other side of the interstate. Of course mine is in a tiny sealed box, about 0.8 - 0.85 cubic foot. If you want SPL with a single sub I would go ported or bandpass. Be sure to use an infrasonic filter to cut the lows below the tuning frequency.

If you want a single 12" MD, in a tiny sealed box let me know. I also have an MTX 4320, 60 X 4 or 250 X 2 bridged 4 ohm at 12.5 volts DC. The amp is a great match to the single dual 4 ohm voice coil sub.