my .02$. ASE master tech by trade, specializing in light truck diesels, esp GMs, since 04. later 03-04 duramax's didnt seem to have have head gasket problems, 01's and early 02's did, there was a design change. 04.5-05 duramax lly's had head gasket issues, to much heat under hood, poor cooling system passage design in the head. Also had egr and some turbo issues due to the turbo mouthpiece diesign. Generally, if you take care of the egr, pcv and mouthpiece, once you replace head gaskets, usually not to big of a deal, studs are good upgrade. Keep tunes up to 100horse, and your shouldnt have issues. 01-04 dmaxs had injector issues mostly. 03 cummins common rails have close to same design as lb7 injector and have some the same issues, but not like the dmaxs. Ford 6.0s, once your stud em, egr delete them , replace oil cooler, minimal issues. I usually do 6.0's for $2800 parts and labor.
