FWIW, I use one of these, along with two of the M-Design Eleganza Bellas (smaller, different shape, 12" Aurasound driver, plate amp not currently available) in my primary system.
This sub is absolutely phenomenal. The Aurasound drivers are peerless (no pun intended) and the cabinetry is beautifully executed.
I wish I had only paid $900 for mine...what a steal for someone with a vehicle large enough to cart away a 200+ lb, gigantic pie wedge in the Bay Area!
M-Design is gone as a company, but if the amp dies the Dayton SPA-1000 is a drop in replacement. (Not that I know of any issues with the amp, just saying because that parts availability is a valid concern when a company isn't around to support product.)