Hi,
I have owned in succession the Sophias, 7's+ WatchDog and now the Maxx 2's sans WatchDog. When I initially purchased the Maxx 2's I too was concerned as I had a room with dimensions on the small side 19 X 16 X 8 --plus bad dimensions (the 16 w X 8 h) which resulted in a noticeable 40-50hz bump. I'll just state that the Maxx 2's solved all bass articulation and weight problems to the degree that I thought the WatchDog expendable, and in my room they literally eliminated the bass issues I had with the 7's--which most owners will acknowledge have a slight forwardness in the upper-mid bass. I think in part the Maxx 2's cabinet size acts to diffuse unwanted standing waves near corners, though I suggest bringing them out as far as is reasonable in your room for maximum stage depth and clarity.
I now have a new home with a specially designed room by Rives Audio with roughly double the size and the results were that much more astounding--although I could have lived happily with the Maxx 2's in my older room and home. Amps with some good power are recommended IMO although they could be driven easily by the Lamm ML2's (18w)--I use the OTL 200watt Atmasphere MA2 mk2.3's. I do not think you would EVER regret the upgrade. From the 6's to the Maxx or Maxx 2 is not subtle in any way and in some ways, they are entirely different speakers, with the Maxx 2's holding the line between the richness of the best Sonus Faber speaker (Stradivarius) and the detail and laser-like articulation of the 6's/7's.
Hope this helps!
Grant