Bryston monoblocks and Parasound are often recommended for Magnepans.
Other than biamping as Teajay mentions above, it seems the consensus is that more power yields a bigger benefit than incremental increases in quality.
I have always wondered about Pass Labs for my Tympanis, but for some reason, no one seems to ever shout Pass from the rooftops when recommending amps for these speakers.
So you might very well improve upon your current set up and good luck.