Your room is a similar size to mine. In-ceiling M3s will give you a better low frequency response for Atmos than M2s. The M2s might bottom out depending on the volume and cross-over frequency.
I know you didn't ask but I have to say it. Plan on trading in the 150 for the 160v4 - best thing I did next to trading in my 600v2 for the 800v4. As for the M22s, maybe one day you might want to try the M5HP. As for Klipsch, they've never engineered a sub they can be proud of.
How did you decide on bipolar speakers for the rears rather than quadpolars like the QS10HP?
