Ultimate PreAmps-CAT SL-1 Ultimate vs. ?

I have a CAT Ultimate and am interested in auditioning other of the absolutely top preamps against it. As I am building a second system even as I upgrade the first, I want to know if there are other preamps that anyone thinks are equal or best the CAT. I lean towards a preamp over a linestage, but will consider linestages. I am targeting for audition ATMA-SPERE MP-1 MK 2, Spectral DMC-30, Thor Audio TA-2000, Blue Circle 3000, Mark Levinson No. 32 and Ayre K1. Any help you can give me on comparisons of sound characteristics of these preamps vs. the CAT will be appreciated, as some of this equipment is difficult to find what with small dealer networks etc. Please don't reply if you have not directly heard or cannot compare the CAT vs. other preamps which you think are equal or better. Comparison vs. the CAT of any vintage is OK. I currently have, and intend to keep, Pass Aleph 4, CAT, Plinius SA-100 MK III. I also have Snell C/V loudspeakers and a Philips CD-80 CD player. These will be replaced next year. I use JPS Superconductor interconnects, Kimber 4tc/8tc biwire and Kimber PBJ between CD player and the CAT. Thanks,