I feel like a dork bumping my own weak thread, but there have been some further developments. With about 10 days to make up my mind on the M3s, it appears they may be staying. While listening to some Bob Marley the Bronzes showed some cabinet resonances that I do not care for.
The area the Bronzes had the greatest edge was in the deep bass frequencies, so I hauled out an old (ca.1990) Bose bass module to use as a stand and thought, "Why not try to use this thing as a stand and a sub?"
Lo and behold it seems to work. Didn't seem to muddy up the midrange (though I only had time to listen to one song) and has provided a touch more thump, which the M3s (or any bookshelf speakers) could use.
Oh, and shipping the M3s from Corona, Ca., back to Canada would have been $33 or so.

It came down to:
Monitor Audio Bronze 2 ($400 + tax + shipping M3s back to Great White North) for about $465.
OR
Axiom M3s paired with a butt-kickin' antique Bose bass module for $275.