Audio Research pre & Krell amps?

I have used the LS-16MKII with my 700CX and hated it but I also hated the LS-16 in other systems.

I am mainly interested in the Ref.3. Not sure if it will be a little to thin in my system or not.
I have used several SS preamps and none have given me the pleasure of the better tubed pres. I have owned the Ayre K-1xe, Krell KRC-HR, and still have the Sim P-5. The Krell was not as nice as the other two. I slightly prefer the Singlepower I am using now over the VTL 7.5 in my system. If my amps had the cast inputs I would try the other Krell preamps.
Just wanted to know what others have decided when matching up the ARC/Krell combo. I hate to audition from a shop, when I know I will end up buying used. Thanks for any help.
I am using the FPB 650M monos. If they ever break, or I come into some cash I will upgrade to the (used) 750MCX amps.

CAST is thinner sounding so don't be anxious for an amp upgrade. As I said, I've owned this stuff and the ref 3 will sound big and inflated but incredibly powerfull. The lack of transparency and detail was a problem for me. The KCT is tonaly the same, slightly less woody sounding but warm, dynamic and very alive sounding...much better than the older krc-HR!