I use a pair of GFA-545's to drive the rear speakers and rear sub with surround material. In the past I've had and used a GFA-535 and GFA-555. I have plenty of time listening to a GFA-585 that a buddy uses to drive Maggy 3.6R's. IMO the GFA-535 is the best sounding of them all. It's only 80WPC but acts like more. Driving a pair of MMG's with a GFA-535 and a powered sub woofer should sound very good.

edit:
I should change my sig to show the 545's instead of the no longer used Hafler's.