The price may have to do with options. The phono stage was a very rare option and few were made with it. The other only option was a remote. So, if you see one with both a phono and remote then $2,500 is about what they are going for.
One without out those options should be about a grand or so cheaper.
I bought one when they first came out, without the phono stage and at that time the remote wasn't even an option.
I still have it, matter of fact Joseph Chow of Audio Horizons fame is in the process of completely rebuilding it and modifying it to make it the ultimate Sunfire pre! Cutf V caps, Elma 47 step attenuator, tube regulated power supply etc...
I've loved mine for many years and they are well built and work. Nothing real hard or impossible to fix or repair. I think it was one of the all time sleepers in audio.