I think that judging by pics and description ( you quoted seller right?), he looks like the type to have it all done properly. I didn't see a mention of the KDP being pinned or if the transfer/lift pump is updated. The 12 valve is not known to have pump failures, but when pushing that much fuel it might be worth asking the question. Otherwise, buy it and then get an offroad trailer for extra gear when you have the 'charger full of humans. Keeps the elk, deer etc off the carpets that way too!
I searched for diesel chargers last night in a fit of envy... Found one in Ohio that doesn't even come into the same league, let alone ballpark for $8k I think. As said above, a keeper for sure!