I now have the m5 in the living room and the M100s in my main space. When I was powering the m5 with my 17 year old Denon, I needed a sub and port plugs. I replaced the Denon with a 2 channel pioneer and no port plugs and no sub needed. It's like a whole different system! What do you think of that?

With the M5s you need stands. The best way to kill their sound is to put them in a bookcase... Lol. The M5s are 5 dB less sensitive than my M100s. So make sure you have enough power. Of course if you want the ultimate in realism, pick up the M100s in refurb or b stock. But I'll tell you the M5s are close. Think of it this way, the M3s are on one end of the spectrum and the M100s on the other. The M5s are wayyyy close to the M100s. I keep saying the m100s are for the 1%.

If the m5 lacks bass in your system, it will not be the m5's fault but rather your electronics!