I am currently using M60s as mains in a 12x12' TV room in the basement. I love the detail at any volume level. I can't imagine getting any clearer but it could be the old "don't know what your missing" syndrome.
I am not happy with bass in my room. I compare them directly to a second set of M60s I have in a much bigger and odd shaped room upstairs. It's music only and for that I get very pleasing bass upstairs and even disconnected the little sub I had there for a bit. It's pleasant, solid and consistent.
Alternatively in the basement room, I get disappointingly weak bass in the center of the room and boomy bass in the corners if I turn it up to compensate. I don't blame the speakers though. It's definitely my square. hard floored lightly furnished room.
If I was not moving this stuff to a new room, I would definitely be considering trying multiple subs to try and help out in there.
