Just set up a denon 3313ic AVR with a 5.1 surround sound. I also have a set of outside speakers running off the zone 2 secondary amp. I would like to add a four channel amp off the zone 3 pre out to power a set of 20-100w, 8 ohm polk in wall speakers in two other rooms in my home. Any recommendations for a suitable amp? Nothing fancy, I will be using the denon for input source and volume control. Thanks for any input.