I have heard good and bad things about the Duramax as well, like the service manager said at Ford, with all the new diesels, gas burners now you either get a good one or a bad one. So seems consistency is the problem now days in producing quality engines, out all the engines produced I hear the least complaints from Cummins owners. Sounds like you have good luck with them, if the Cummins doesn't work out I will definitely look into the Chevy's / GMC's. Thanks