The design is good (Dual Opposed 12" Drivers ) and it looks really nice, but IMO for a list price of $4500, you would be nuts to buy a sub like that...
There are far better products out there for the money, in fact I just built 3 subs that will each individually blow 3- 4 of those combined out of the water for @ $4k a piece...
Link
My suggestion is you save some money and take a look at a Seaton Submersive, which are beautiful - come with the same design - but have Dual 15" drivers for 1/2 the price as the B&W.
See here for information about the Submersive...
http://www.seaton-sound-forum.com/post?id=4292198#1
Full Disclosure:
I generally will build my own subs, but I have a JL F112 in my bedroom and I am replacing it with the Submersive. I have seen the Submersive and heard/felt them in action, no question it is a top quality product. Its an extremely musical sub that doubles as a great Home Theater deep bass sub...
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