I have had my M3 Turbo s's since they came out and love them. Bit i have always had my custom built sub running with them to augment to bass. I recently purchased a PS Audio Gain Cell DAC which is a killer unit in its own right and punches way above its price level IMO. One thing i noticed as this unit breaks in is that the M3's are starting to come to their own in the bass department. I even played Daft Punks "doing it right" which everyone knows has a chorus with bass that can hurt speakers. the M3's not only put out the bass they seemed to smooth it out to the point that you can tell the cleanness of the synthesized tracks. I think back when I hear someone complain that the M3 has no low bass they are suffering from their front end not allowing them to do their thing. Goes back to the old Synergy and good equipment matching for the speakers you are running. I have sit here all morning playing tracks that used to require a sub to be full and haven't felt compelled to turn it on even once.
For all you soon to be owners or people looking at these speakers. Please be advised that careful equipment choices are mandatory to get these speakers to be what they can be. I ran my NuForce p8 for years and while the midrange and highs where fine the bass was always just not there. I am now just breaking in the Gain Cell DAC and this thing going through my Pass Labs amp is making my speakers happy as I've ever heard them