Forgot to answer one of your questions:
Whether I thought the $3,000 cost of the DEBRA was worth the cost?
Unequivocally, yes. I honestly can't count the number of times I've been listening to music and the music calls for deeper bass (acoustic, percussion or electronic) and the DBA system just powerfully, naturally and seemingly effortlessly reproduces the lowest octaves and blends so seamlessly with the Magnepans reproducing everything else that the result is a sound stage illusion that just sounds like a beautifully synchronized realistic whole; like the actual musicians are playing in my living room or as if I've been transported to the venue, depending on the recording.
Logically I know it's a sound stage illusion but it's uncanny how I perceive the bass, even though it is monaural, as emanating from the proper instruments within this illusionary and 3D sound stage. It's really quite impressive and enjoyable. .
I think paying attention to details and being precise in setting up a DBA is critical to getting good results; things like following the progressive locating procedure for properly positioning each of the 4 subs in the room, using trial and error to set the crossover at the correct hz (I found 40hz worked best in my system), determining the correct relative volume of the DBAS (in relation to your main speakers) by precise setting of the supplied sub amp's rotary volume control knob (mine is set between the 9 and 10 o'clock position) and whether to run your main speakers full range or use a filter to limit their lower frequency duties (Mine run full range without restriction).
Fortunately, this rather elaborate setup process only needs to be done well once. You're able to just enjoy your music with consistently stellar performance until you decide to move or upgrade your main speakers.
Lastly, I wanted to mention that you can also construct your own custom DBA by using 4 subs of your own choosing. However, this is likely to be significantly more expensive than a DEBRA or SWARM complete system with the 'law of diminishing returns' also needing to be considered.
Thanks,
Tim