Axiom specs the M22 at 89dB for 1 watt at the standard 1 meter distance. In typical home rooms the sound level drops off 3dB per doubling of distance. At 13 feet, which is almost exactly 4 meters, the sound level for 1 watt would be a still comfortably loud 83dB for 1 speaker. If both front speakers were playing at that level, the level at the listening position would be 3dB higher, e.g., 86dB. In order to allow for the most dynamic source material, it's suggested that as much as 20dB of headroom(i.e., 100 times the power)be allowed for. This would handle extremely loud brief peaks at 103dB(1 speaker)and 106dB(two front speakers). It appears that 100 watts for brief split-second peaks should meet your needs.
You also mentioned Onkyo as a possible selection, and I'll suggest that you consider an outstanding buy available at this time on the Onkyo 180 factory refurbished unit(which should be at least as reliable as a brand-new one)from
Accessories4less here for about $350 shipped. This should meet your power needs and more than meet your requirements for up-to-date features.
