wattage depends on what is being produced by those speakers. An explosion coming from the front speakers will require more power (watts) then surround affects in the surrounds. Also, for 5.1 you don't have rears, or should not, you have side surrounds.

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