The answer to op is yes there have been significant changes in diesel engines (gas too) over the last decade. Some are for the better and some may be problematic. I am not a tech or particularly biased user. I own my first diesel pusher, Cummins isc 2012 with def. From the pov of a fulltimer who runs maybe 15k miles a year I expect the engine to outlive me. It is quiet, the loudest noise is the radiator fan. It doesn't stink. It is 50% more fuel efficient than my 2004 gasser. Dang about every 3 months or so I need to put some def in the tank. At 2.79/gal (at the pump) it may cost me a penny a mile or 2, less if I stay out of cities and out on the open road.
The benefit to the environment of the epa requirements cannot be denied. I don't worry about it for me, I'm over 70, but I have 5 grandsons and I'd like them to be able to breath clean air. Not to mention their children. Loving the old ways may feel good, but it is pretty selfish. Leaded gas spread lead through the atmosphere and reduced the iq of everyone. It's gone thanks to got regulation. End of rant!
