It really is up to you on whether the condition of his is as good as yours.
Do you LIKE his truck, or is it a girly-infatuation that a few problems will make you mad and disenchanted with the deal?
In the end is it really what you LIKE, or is an old boxy Dodge your cup of tea?
Are you really willing to give up what you have for a "new" experience?
If I were going to beat him down based on the pump issues, I'd find out what it would cost to put it back together with the VP, cost of R&R, cost of replacement pump and any consequential costs.
Don't forget, when a VP comes apart, sometimes it'll take injectors with it.
If it runs smooth now, the injectors are probably okay.
In a way, if a few grand comes between you and your decision, I really think you have the answer, especially since you'd ignore the VP and P-pump it.
Beat him up a few grand, all he can say is no.
Mark.