The D-200 is a great amp for driving the Mahlers. I have Mahlers being driven by the D-200 amp. My center channel is driven by my receiver. I have not invested in a center channel amp. Personally, I think matching amps for HT is over rated. Matching speakers is very important (at least the center with the L and R speakers, but as long as you have a HT preamp that can match volumes (my receiver even has equalization for speaker correction and room correction [oh the fun HT is, never would I put something like this in my 2 channel setup]).
KF
KF