To my understanding dpf filters were installed in 2007 trucks and newer from manuafacturer. Scr on 2010 and newer from manuafacturer but I am not sure about the doc's (diesel oxidation catalyst)? Do all trucks that have dpf filters installed from the manufacturer in 2007 have doc's? Or what year were they put on? Looking to get newer trucks to attract drivers, are the 16 or 17 models any better on the emission component problems or enough miles been laid down to tell yet?