IDK what to do. I want a diesel for a daily driver and to pull my 8000 lb 5th wheel. I have read and studied the 6.0 and am familiar with the problems and fixes for this engine. I have driven both the 6.0 and the 08 6.4, which is miles ahead of the 6.0 trucks (IMHO). However, the 6.4 has it's own set of problems, most of which seem to be much more expensive to fix. Besides the DPF, fuel system contamination seems to be the greatest threat. When buying a used truck it is more difficult to determine the maintenance history to know if the PO changed the oil and all filters as he should or maintained the fuel system to prevent contamination. I would prefer to have an 08, 6.4 but have gotten scared of the reliability of a used one. I would plan to keep a truck for 250k miles at least. Anyone have any bits of wisdom or encouragement?