Discussion of or questions on the BMS driver and its measurements should go here.
This is one of the best all around bass drivers I've found yet. It's got enough displacement to legitimately reproduce the low stuff, it is quite efficient and doesn't require much more than a 1kw amp to get most of its performance, its coil will handle that much amp all day long without breaking a sweat. It is rugged and immune to bottoming for the most part, with good overload characteristics, it has very low distortion thanks to the triple shorting rings and it has an excellent top end that can easily be used up into the 450Hz range or wherever you want to cross it over to control your dispersion pattern hand off to your mid driver up top. Did I mention it weighs less than 24lbs?