The only problem I could see, and it's only because I had just gone thru it myself during the last few months, is to comment that the M3s may just be a tad too small for the size of your room.
I had already been using M3s for a few years before we moved into this new house, and they worked beautifully in a somewhat smaller room in the older home. They tried admirably in this room, but on loud passages in action movies they came across as somewhat stresed.
While M3s are great sounding speakers, in that sized room they could end up as a disapointment as main speakers in an HT system.
(I went with M50s cause they sound so darn close to those M3s. I just couldn't bear to part with them!!!)
