My room is 31ft x 30ft x 9ft and for the most part the Denon 2805 did just fine by itself. I do however use Odyssey monoblocks to drive my 80's. Unless you really crank it up loud you may not need seperate amps. The 80's are very efficient and don't take much power to play real loud.

M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85