Ayre K-5xe / tube preamp s comparisons?

I'm strongly considering switching to a tube preamp for my system, to get a bit of that 'tube magic.' I currently have a Linn LP12, Ayre CX-7e cd player, an Ayre K-3x preamp, Ayre V-5xe amp, and Thiel 2.3 speakers. The i-c's are Cardas Golden Cross, and the spkr cable is Cardas Cross.

I've heard great things about the Aesthetix Calypso, CAT SL-1, and VTL 5.5 (my price range doesn't go above these)- and of course, the K-5xe, which given Ayre's designs, has sonic attributes comparable to certain aspects of tubes. (The phono stage is another matter altogether, and I should add that I don't yet know if I should go with something like a Janus, or a P-5xe plus Calypso, or one of the others).

I've found it hard to make definitive judgments about components based upon brief store auditions alone, especially outside my current chain of components and room environment. Also, I don't know of any dealers in this area who carry both Ayre and tube gear, or all three of the tube preamps mentioned. I'd therefore GREATLY appreciate feedback from people who have compared two or more of these units re. their acoustic similarities or differences; how great the differences are (or not); (other) deal-maker or -breaker factors if sound is comparable, including comparisons to the K-5xe; and the like.