I have been looking at several used power amps, one is a Kenwood 125x6, another Adcom 3x100, 2x60 and the other Rotel 5x100. Utilizing a Marantz 7400 as a pre/pro, would there be any "noticeble" difference between the 125 watts vs 100 watts? Also, would any of these amps be "brighter" than the other. I am looking to avoid adding any brightness to the sound. Thanks.