Worth checking their provenance, and being 100% certain which model they are, and when built. They date from about 2003, I think.
I believe all Sfs come with 'socks' that fit over the full height of cabinet (mine did, and I've seen them elsewhere)Having the socks and original packing would be pretty essential IMO, both for completeness and enabling safe transit.
There were later stand-mount Auditor M models, reviewed here:- http://www.whathifi.com/review/sonus-faber-cremona-auditor-m
I recently heard the current Cremona M and it was absolutely lush. Of course, they look fabulous, which helps. And I am bit of a convert - not everyone is.
The point above about matching is well made. I'm not familiar with the sound of your gear, but Audio Research valve gear is often paired with Sfs. I'm not assuming valve/tube = warm, at least not these days. And I wouldn't necessarily describe the SF sound as warm - that's too simplistic. Definitely not harsh, brittle, sizzling or anything like that. But they do have an innately musical sound, which I describe as sounding natural - like the bow on a violin string, or the sound of a piano on a wooden stage. The US magazine called Sterophile tested them with Unison Research, so maybe they are a good match?
I hope you get lucky!