I think that I'd probably go with three matched amps for the front if your budget will allow it. However, if you aren't clipping your current 85watt amp currently, there's not a compelling reason to replace it for the center channel. How's that for a vague answer? It really depends on your budget: three matched amps for the front would be an ideal situation, but if you aren't clipping your center now, you could get away with keeping your current amp and possibly upgrading the center at a later date.

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The Soundhound Theater