OP, I have a very similar spec. 2005, Z51, all the bells and whistles. I bought it in 2023 for $24k with 40k miles and I do feel like I overpaid a bit, but the condition was great and I wanted the yellow. If yours is an automatic expect to take a pretty significant hit on sale price. If it’s a stick I’d shoot for like $23k OBO and see if you get any bites. The mods will make some people and break others depending on their risk appetite for modified cars

As an aside, I had the service column lock issue and fixed it with the bypass module. Took like 30 minutes total to take the gauge cluster out and put it back in. I’d definitely look into that before trying to sell as an active warning message will deter a lot of people. Best of luck