The MMG-Ws are targeted as surround speakers, not mains. My speaker setup:
MMG | L/R mains | 50hz - 24 kHz
MMG-W | surrounds | 100Hz - 16kHz
MMG-C | center | 100Hz - 16kHz
Pinnacle Baby Boomer | sub | 23Hz - ??
Heh...haven't even used the -C yet as I don't have an amp for it. Doh!! At any rate, I would *not* use the MMG-Ws as mains - their freq response just doesn't cut it. I've found the W passable - but not stellar - for HT stuff, even given the freq response. If you go with the regular MMGs as mains, you'll want a fast sub if you like your bass, IME. MMGs pop up on Audiogon for ~$300-350 or so pretty regularly, if memory serves. Even after a year-plus I'm still stunned by the Maggie sound!
And yes, Moke - they require an amp that can handle 4-ohms.