I'm not trying to start an argument here, but I often find that center channel speakers often have trouble keeping up with the rest of the system. A different solution that may work in this case would be, if you have 2 available channels, you may want to consider getting a pair of speakers as your center channel. If you put one speaker on each side of the screen and run each one full range powered by their own channel, it will put a very strong image in the center of your screen. To get an example of what I'm talking about, listen to a mono recording. That will be pretty close to how a center channel will sound if done this way.
Amp connection question
I'm going to be adding a center channel speaker and am looking at inexpensive used amps on c-list. My question is can I, and is there a benefit to, splitting my single center channel rca output on my pre-amp and running it into both left and right inputs on an amp, then bi-amping my center channel? Would this work and is there a benefit to doing this? Thanks!