On the plus side M3s do sound excellent without a sub. I used M2s for a while as computer speakers and even with a sub found them lacking (though they were very clear and precise, just "lacking" that certain je ne sais quoi). I now use M22s for the computer with a sub and love them. My M3s serve as a standalone 2.0 system in the bedroom and I love them as well.

M80s/VP160/QS8s/EP350; M22s; M3s.