this is the exact setup i was looking to buy new, they arent allowed to sell them right now, (thanks VW) until they address EPA concerns about the auxillary (read: engine failsafe) emmision control programs. There will be a recall with a new engine tune coming for the trucks already sold. (hopefully the 18s will be available in the spring, but no guarantee until it happens)
also do a search on the 1500diesel forums about this, the 14s had a run of bad oil coolers which were failing mixing oil and coolant, this was causing bearings to go out, there are guys with 30k with a new engine in the truck already (there are also guys with over 300k with the original engine still in it. very hit or miss for the 14s) Also note that the used ones are demanding a premium right now because they arent making new ones, they WILL run disproportionately expensive compared to a gas truck from the same year. some guys on the forums are getting offers for the trucks with up to 100k to buy them back for they sold for new (not everyone, but i have heard a few stories about it).
i was also talking to someone at the waway ride on thanksgiving, he said he only gets about 24-25 mixed driving from his, not the 29 advertised. i get 20-21 out of my HEMI, is that 3-4mpg worth the extra up front expense? you decide.
All i can say is with the current events relating to the trucks and the supposedly coming resolutions im happy with my hemi, especially for the price.