What sub for B&W HTM1d and 802ds?

I have been turning my listening room into a ht and want to get a subwoofer. I realize the easiest thing to do is get the B&W asw 825 or the 855, but is it the best . I am using it for sacd and for the 5.1 outputs on my oppo player . Any suggestions? The room is 16 by 13 by 7ft ceiling. I have put oc 704 on the walls, 12 2x4 panels covered with Guilford of main acoustic fabric. I took out the corners by framing and sheetrocking.The walls are double sheetrock with more ridged fiberglass behind . Its in the basement so I am a little concerned with the concrete slab,How do you move concret?(I had wall to wall carpet installed). I am using 3 VTL mb450 tube mono blocks for the front three channels and a cj mv75 for the rears. Will the 825 or the 855 mix well with the tubes?Thanks Craig
1. You do not move concrete and that's OK.

2. I am afraid you left out all the useful info, so...

3. What pre/pro are you using and what bass management does it have?

4. Have you measured your room's modes or, even, just the FR?

VTL 5.5 and and a Sony TA-P9000Es This preamp is a very pure multi channel analog preamp that allows TWO sets of 5.1 analog inputs I am using the oppo 5.1 outs and the sony sacd outs.It does allow for an HT bypass of another set of 5.1 inputs AND a bypassed set of stereo inputs (both bypass inputs are passed thru unaffected by volume control).
No Bass Managment on either, but the oppo player has some. I want to get a processar for the hdtv cable.But so far mostly I have have just been listening to sacd ,phono and dvd. and just two channel audio for cable.

I havn't mesured any thing .What do I need to do it. I have tried to make the room as dead as possible double sheetrock lots of insulaton and wall treatments to the first reflexion points. I put six inch crown and sheet rocked the corners . Thanks for any suggestions.
I have 800D and use the 855 for my sub. It's a great seamless combination. For your room, you might be able to do fine w/ the 825. By the way I did try the Velodyne DD15 but that did not match as well as the 855.
I do not believe that matching the sub to the speakers (within limits) is as important as matching the sub to the room. That said, I have no experience with the 855 or any other B&W sub. I am using the JL Audio f113 with the 802Ds (L/C/R) and it works well in my 15'x26'x8' room. In your room, the f112 would probably do as well. These feature an excellent automatic parametric EQ that makes room-matching simple.

Thanks those are great suggestions. Does the 855 or the 825 have any Kind of parametric eq ? I like the idea of all my speakers having the same Rohacell woofer ,but man that Gotham could move concrete LOL. If I could only find a deal on one of those....
Thanks Craig