Have had experience with both the FPB 300 & 600 series amps by krell...they are neither bright or lifeless, they are some of the most incredible amps on the market today, the top end is smooth, listenable for hours and the bass, well I'll just say that it is the tightess, fastest and articulate that I have ever heard. The FPB600 would not be an overkill for your speakers, more than likely they would probably have your B&W's dancing in your room, I must say that a tube preamp worked best in my setup with the FPB600.