I also own CarderSound Madison speakers. Presently I'm using them with Mike R modified Fostex FE206E drivers and I've never been happier in my life.
That said, I'm curious if you found replacing the Fostex FE206E with Coral Beta 8 was a big improvement? If so, can you describe what the sonic improvements were?
I've included a photo of my system which consists of a Mastersound Reference 845 integrated, SET amp. A BlueNote Stibbert CD player, CarderSound Madison speakers, Mike R interconnects and speakerwires and Stealth Audio M-21 Super power cords.