First thing you need to do is figure out whether it's the speakers or the placement. Is there some spot where you could TEMPORARILY set up the speakers so they are :
~ 6-8 feet apart
~ 2 feet off the ground (stack some small cardboard boxes or something)
~ 2 feet from the wall, with empty space behind them
- front of speakers protruding over whatever is holding them up
You might need some extra speaker wire for the temporary hookup but it's worth it. If you like the sound of the speakers in this position then we just need to play with your cabinet setup to reduce its impact. If you don't like the sound of the speakers there, then think about exchanging for M2 or M22. M2 has more midrange and less bass; M22 has more midrange and about the same bass but a bit "flatter". My first thought is that you sound like an M2/M22 listener with M3 speakers
If you are listening mostly to jazz, chamber music or comparable pop / rock then you will probably be OK with M2s sans sub. Believe it or not I would even include a lot of 70s "progressive rock" in that category... Dance on a Volcano and Echoes sound better than you would think on M2s. ELP-type groups will suck a bit on M2s, as will most orchestral works including most opera.
If you live near Toronto we can swap M2s for M3s and see how they sound.
