I guess they didn't get the memo that doubling the cone area allows for +6db... without x4 the power and x16 the heat and x32 the THD%. LOL!
They will learn and adapt. (Or not... )
Looks like a custom build for single or dual small subwoofer diameter class in car DB drag, not sure they'd get it approved as anything less than 12" class though because of the amount of the surround that behaves like part of the cone.
cms, aka driver diaphragm suspension mechanical compliance: 0.000065 meter/Newton or in standard form 6.5e-05 m/N. (smaller number is better)
rms, aka driver diaphragm suspension mechanical resistance: 6.41 Newton.sec/meter. (higher number is better)