I agree, the CAT preamps are wonderful and quite a bargain. From what I was told, thier reference amp is $10,000 more than the one that is essentially identical to it, other than an incredibly expensive power supply. I have heard that they are wonderful. Unfortunately there is no marketing effort at all and it is almost impossible to get a call back from anyone other than one tech who could not answer my questions. I may be wrong, but I think they are only single ended.
They came highly recommended to me by someone at Wilson. He owned them and was very pleased until he replaced them with Atma-sphere. He now LOVES the Atma-spheres.
What speakers are you using?