Norb, welcome. As always, the question of how much maximum power capacity is needed in a receiver will vary with factors such as your distance from the speakers, how loud an average level you listen at and how wide the dynamic range of the material that you play is. It can be said that in the vast majority of home listening situations that the 1907 has plenty of power for those Axioms, which use about 1 watt at a comfortably loud listening level, while split-second peaks, depending on the material, might hit the 100 watt area.
There're more powerful subs than the PW2100, but certainly it can extend the bass coverage of M60s very usefully.
