I think you've answered your own question. Keep the Sonus Fabers but try them with both amps and see which you prefer.
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You may be preferring the amp as Artmaltman says. I've heard the Meridian+Concentra (an excellent combination btw) with both the Proac and Sonus Faber GP, and I definitely preferred the Proac. The SF sounded a little hi-fi'ish to me. On the other hand, if you had said the SF EAII, then you'd have a contest.