I'm using a Parasound HCS-855a to power my 2Ce. I am using 2 channels to each speaker and no complaints with the set up. Even rated at 85x5, it's proven to be more the n3 times more powerful then the Pioneer Elite receiver that acts as the processor (Rated at 110x7).
Parasound, Bryston, B&K, Carver are some brands that can be found used for a great value.