Looks like most of the diesel engine problems on the rear diesel engine are cooling due to dirty coolers. They run in a lot of dirt/dust.
Won't have that problem with a front diesel. All of the heavy duty diesel trucks are front diesel/cooler.
Seems a little high but it is a good quality unit and condition means everything. Also if a dealer, he offers a trade in and financing.
Tried to PM you and was blocked. We have a 2005 KS for sale, PM me if desired