Save yourself the pain, get a REL (ST series) and forget the rest. You have a very high-quality system which means the servo subs are out (they will sound maddeningly slow and thuddy), and your speakers can easily go full-range so there is no point in screwing up the sound by putting a crossover in there. The REL ST series is by far the most musical sub out there, and will integrate perfectly (use the high-level connection and set the crossover point a lot lower than you think it should be- this means for your speakers, probably around 28-30 Hz!). Don't be put off by the 10" driver, it can do things your ears won't believe. First choice in the $2000 range would be a used Stadium III; next is a new Storm III or used Stadium II. I'm not affiliated with REL, I just think that if you're looking for a MUSIC sub there is no comparison. See www.rel.net.
