Capn Pickard,

M2's are a little small for that room size, but as long as there is a good sub it shouldn't be that much of a problem. They just might sound a little 'thin'. Have you considered maybe M3's?

I would suggest a VP100 as a center. It will help pronounce the vocals better than an M2. Another option would be to see if Axiom still has a VP50 lying around. It is slightly smaller than the VP100. Due to centers lying flat, they are also easier to place above a TV.