Well, aside from resurrecting a ten year old thread when you sell your truck it will by definition be for what it's worth on that day, with those two people making the deal. Anything else is "woulda-coulda-shoulda". If you want top dollar, make sure it's spotlessly clean, operating perfectly, invest in a way to prove the condition (thinking Scangauge or something) and sell it to someone who knows absolutely nothing about 6.0L PSD engines. Otherwise it's just an old truck...

Brian