Man! My '03 is still just a puppy with a tad under 280K on the clock. Biggest expenses were two water pumps, two APPS units and a new power steering pump with reservoir upgrade. A few front bearing assemblies, too. But that's a Dodge thing, not a Cummins thing. Still running the original injectors without problems and still getting great fuel economy. Averaging just under 17.5 MPG over the life of the truck and including all types of driving.