Adcom 5503 or two 555 IIs?

I am getting a 5.1 system together using 4 KEF Reference 201s, a 202C and a sub. Right now, I have an Adcom 555 II powering two of the 201s using an old receiver as a pre amp. I absolutely love the 555 II. When I go to the 5.1, should I get a 5503 for the fronts and move the 555 II to the rears or should I get two 555 IIs and just use one channel on one of them for the center? Thanks in advance.

I should have said above "two MORE 555 IIs" instead of "two 555 IIs" so I would have a total of three 555 IIs driving the 5.1 system.

I would say that if you want to stick to Adcom, go with the 5503. If you listen to a lot of two channel and decide you like the 555 II better, you can always set it up to use the 5503 for the center and rears. I don't know much about your speakers, but do you really need that much power for your rears? Maybe if you listen to a lot of music in 5.1, but if this is just for HT, there are a lot of 100 watt x3 amps out there that are much cheaper than the Adcom. Maybe a Rotel RB 976 would be a good amp. It is 6 channels but can be bridged to be around 100 watts x3. The Rotel would be half the price of the Adcom.
I have been listening to a lot of 5.1 music so I felt that the front three needed to be of the same amp. I was mainly trying to find out what people thought of the differences between the 5503 and the 555 II. I really appreciate the response.