It's been my experience that passive biamping has little to no effect on the sound of the system (assuming you are using reasonably thick wire in the first place). What center are you using and how is it placed in your HT? Speaker selection, placement and room acoustics play a much larger role in sound reproduction...
Thats right. But I will not be using an active crossover between the preamp and amp. I will just use two separately amplified full range signals to the speaker.