Unless you find a buyer with your EXACT taste who wants the EXACT build that you put together, there are going to be parts that you paid good money for which hold no value to the buyer. This is why you never get nearly the money back that you invested into a build, regardless of the quality and attention to detail put into it.
I think most Z enthusiasts would rather spend 50k+ buying a relatively stock Z and building it exactly to their liking than spending 40k on a Z that may at best be "close" to what they want.