IMHO that is the most you will be able to get. I have 32K miles on my Z and it is pretty much spotless. I have put WAY too much money into modding my Z so i know I will have to keep it forever. You have one beautiful Z there but I doubt you will be able to fins someone to pay much more than 18K for it. (Blue book is MUCH less than that) That being said you may just want to find a way to keep it. Good luck.