Tech Radar did a review - with tests - of the unit. Here is what they measured:

""In our lab, the model delivered 105W across five channels, and 130W in stereo mode (into 8ohms). Multichannel mixes are simply laid bare in the room and the sound all but leaps out of the speakers, creating the wonderful illusion of a much larger listening environment.""

This means you are going to have 4x105 watts for the M3's - that's going to rock. And Arcam's stuff is just plain great sounding.