Am a Hagerty Driver's Club guy so a bit of bias in full disclosure, but here are a few sources I would start at and with:
Unless you must sell it, I would hold onto it. I have one as well with 29k currently going through NCRS. It is currently a Hill MoE with Crossed Flags coming up in July. I wouldn’t part with it for the world! Add to that Hagerty just listed the 01-04 Z06 on its Bull Market list. A CE is worth even more than the others.
I would try Bring A Trailer first. They are picky about what cars they will list but might accept yours.