The data presented there is taken from Josh's testing, the entirety of which can be viewed on his website. Josh is very knowledgeable and if one likes subs they really should look at the data he posts.
One should be careful when interpreting the data on there, it is easy to look at the CEA numbers and assume one is better than the other. The CEA testing uses "bursts" at 2 meters ground plane. For passive systems Josh uses a K10 and in typical use one does not usually apply such power into their systems. If you honestly have that much power on tap I recommend using the long term sweep as a more accurate guideline, using a bridged K10 into most of these systems for actual use will likely result in damage. Josh knows what he is doing so is able to walk the fine line between getting the most out of them without damaging them. Take a gander at the impedance, voltage applied and distortion sweeps as well to better understand what the system is doing.