REL Stentor III (new, full warranty) -  This is a made in England, audiophile grade, studio standard, full mamma-jamma subwoofer that will stand the test of time as one of the best you can buy regardless of price.  We have opened the box to take a picture and to confirm it is beautiful.  Cherry real wood veneer finish. 

You can hook it up with line-level from your pre-amp, or from the speaker taps to any power amp.  See more info here http://www.sumikoaudio.net/rel/prod_stentor.htm 

The Stentor III is one of the only subs on the market that can be used with Magnaplanar and Martin Logan speakers because it is so fast.  Retail is $6995.  We can’t put a price up here because you don’t get discounts on REL.  But somebody is gonna be happy, and it may as well be you.  Call for price.  Area restrictions may apply.