I own Harbottle subwoofers and Funk Audio subwoofers. They are sister companies. In my opinion these companies represent the state of the art in home audio subwoofer design. I have owned subwoofers from SVS, Rythmik, Rel, JL Audio, Power Sound Audio, and JTR. I have heard just about everything including Perlisten and other expensive manufacturers. Funk Audio and Harbottle are the best I've heard by far.
CEA-2010 is a very simplistic approach to measuring subwoofer performance. It basically just tells you how loud a subwoofer can get within a threshold of very liberal harmonic distortion limits. At the levels of distortion CEA allows playback can be very dirty and audibly distorted. It also says nothing about how well a subwoofer performs within those limits in terms of linearity, compression, other forms of distortion, etc. All of these things are audible and affect subwoofer performance.
Take JTR for example. Their subwoofers have a lot of output as per CEA. When you poke around and look at the data, however, you can see heavy compression occurring at playback levels well below these CEA numbers. This is very much audible and lends itself to the "sound signature" that JTR subwoofers have.
Funk Audio and Harbottle subwoofers are designed to satisfy a very strict set of criteria within their performance envelope. They use huge powerful neodymium motors with underhung oversized voice coils and carefully tuned suspensions so that their output at full power of thousands of watts still has inaudible distortion and vanishly low, inaudible, and very controlled compression. This means that when you look at the numbers at which they rate their subwoofers for max output you are looking at numbers at which the subwoofer performs cleanly and linearly. Most subwoofers lose linearity at significantly lower levels where they go into compression that causes ugly and audible nonharmonic distortion at high levels.
Basically every subwoofer on the market uses an overhung motor design. It's the obvious choice when you want to maximize output relative to cost. Most use ferrite motors as well, since it is a cheaper material to use to get magnetic field strength. They also use smaller 2-3" voice coils, which are lighter and more efficient but have low power handling.
Funk Audio and Harbottle use underhung motors with neodymium magnets and massive 5" voice coils. Designing subwoofers this way is wasteful if the goal is output per dollar, but they are designed with a different goal in mind, namely linearity and accuracy. The end result when you get them dialed in is bass that sounds perfect in every way.