That's a good question. There are a number of things that can be touched on with what seems to be pretty difficult in finding a 12 inch sub that can do this. It seems most of the current dedicated car subs are following this trend where all of the more "higher quality" models of a manufacturer's lines have that super huge surround, a really thick/stiff cone, and a large magnet assembly. The problem with these subs is that those huge surrounds and thick cones typically raise the resonant frequency of the sub and the efficiency of the sub is also compromised. Those subs typically end up with efficiency numbers like 83 DB and people then brag about the power handling and I just shake my head because now instead of being able to throw 300-500 watts at a subwoofer for respectable output you have to send more like 1000 watts to the less efficient subwoofer in order to make up for its lower sensitivity.

Honestly I could be wrong but I dont think you are going to find a subwoofer in the mobile realm that is going to have a low resonant frequency like the discovery (17 hz) , with an 89 dB efficiency, and with such a shallow mounting depth. If I'm not mistaken even Scanspeaks revelator line doesnt have a sub with a resonant frequency as low as the 30 discovery. If it's going to be found it's more than likely going to be in the home side of drivers which is really more of what the discovery is in a sense.

One other sub maybe worth looking at is the SEAS LROY 4 ohm 10 inch. It doesnt have quite the same shallow mounting depth but it has a low resonant frequency along with decent sensitivity ratings. It looks to be built like a tank as well and has a very good amount of xmax. You could probably throw 500-800 watts at this subwoofer in a 1.5 box with no problems. I have not modeled its parameters yet but I'm interested in what kind of volume it needs for a .707 QTC and what the F3 will be...