I'm sure the dealer can offer you that lifetime warranty. It just doesn't come standard on diesels.
I'm very happy with my 6.7. All the power I could ask for and zero problems.
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98.5 2500 4x4 Reg Cab, 6" GrandRock Stacks, Adrenaline w/ Pulse, FASS 150, Isspro egt/boost/fuel, silencer ring MIA, Auto to NV4500 swap, 2.5" level w/ 315 Cooper ST's
07.5 3500 6.7L G56 Manual 4x4 Quad Cab Dually -dpf delete in garage