Hi kamikazi,
My room is not that big - 5.2m x 5.3m - but it did take some effort to get them in the right place to sound just right.
I am using a Krell KSA 150 to drive them - it has enough power - but I would not mind having a KSA 250 or FPB300 to drive them :)
Enjoy the MG12s - the Maggie...