I think that is an outstanding system.
However, you might want to consider getting the Rythmik F12G
http://www.rythmikaudio.com/F12G.html
I say this because when I called Rythmik and asked about their absolute best set-up for music he (the owner - forget his name) suggested a pair or F12G's despite their lower cost (which always impresses me about the integrity of a salesman - or owner in this case).
When I spoke with him, Rythmik was just firming up their agreement with Ascend (and the F12G is not sold via Ascend). I'm not sure if politics may now be at play - it may put him in an awkward position to recommend the F12G's.
You might want to at least give Rythmik a call and see what they say - can't hurt!
The impression I have is that the Rythmik subs (any of them) are excellent for audiophile subs for music (where you are looking for articulation more than output and extension). However, if I was in your shoes, I would wait 2-6 weeks for the upcoming Audioholics review of the Rythmik FV15HP to make sure comments about the larger Rythmik servo sub are in line with your expectations.
Edit: I should clarify that the differences between the F12SE and F12G were never presented by Rythmik as being substantial, just that the F12G was slightly preferred for music and the F12 or F12SE slightly preferred for HT.