A 2003 duramax is a lb7 and they don't have any emissions stuff from the factory. Bad thing is they eat injectors and it's not a cheap replacement. You may get some extra life out of what you have but do plan and budget for injectors in your future. Don't buy a stock replacement when and/or if you do. Look into injectors from somebody like Lincoln Diesel. The lb7 is a great engine other than the injector issues.
