Can't believe you (and when I say you, I mean your wife) are thinking about selling this gorgeous truck. Weren't you just thinking about putting a lift kit on it? Think about how much time you spent trying to get rid of the Chevy lean!
Anyway, I would think you can get every bit of $40k. A dealer would love to have that on the lot and would sell it for $45k.
I would also suggest selling the bell tech kit, since a lowered truck will limit your market. And since most people don't care, might as well sell your esky roof rack. I know someone who would be interested if you consider selling it (wink wink).
Glws