First, my room is volumetrically large with no discernible backwall reinforcement. My box speaker experience includes; Genesis Vs, Usher 6371s, Nearfield Pipedream Accoustics (sans sub woofers), Swan Diva 6s. For OBs; Accoustat 2+2s (2 close friends had custom frame Accoustat 10s, but in very large rooms, both reinforced with dual subs), Magnepan 3.5Rs with and without subs, and currently Emerald Physics KC IIs (with and without subs), and a pair of EP 2.8s on their way (dual 15" + 12" coax drivers).
I have a EP BOM, but the SVS Ultra and Plus subs just don’t marry well without an expensive 3 way active XO; I blew through 4 cheap active XOs, but when they worked, well, there was some magic there.
Unless you are buying huge planar speakers, bass is not likely to have the impact of cone drivers in OB speakers
What I recently discovered was of the many amps I had in the last 4+ years, RIc Shultz’s EVS 1200 has the mid-bass and bass authority none of the others had. I have owned the KCIIs for 3+ years but never heard them as cohesive top to bottom as they sound with 100+ hours on the EVS 1200. This amp could be magic on Maggies as well. A few maggie owners have chimed in that the new IcePower class D is giving them the best sound they've had