The older Krell is a litle dark on top, the bass control is great if the MBL's are spiked on something solid. The best I have heard these speakers, are with MBL 9011 , also a slightly warm amp. I will look for Kraft in my neck of the woods. Good luck with the preamp search!
I also like the 9011's, but they are so pricy! And although I primarily have heard the 9011's at shows, Krafts may be better in terms of liquidity, continuity, and getting that midbass melon to growl just right. There's some rightness about Class A that class ab just can't do.
If you try it, please post your thoughts.