A lot of info in this post!
Just to step back a bit and breath...
The biggest difference I noted when going from a gas Class a to a DP was the quiet.
Second was the smoothness.
Third was how much easier it is to drive.
We roll along in smooth silence. We can talk to eachother if we choose, or listen to the radio, or simply listen to our own thoughts.
Silly details like skinny lanes, passing trucks, bumps, and hills (and mountains) become unimportanmt. Not noticeable. In the background of the experience.
On the emission control thing... Prior to 2008, highway diesels didn't have any ecternal emission control devices.
In 2008 / 2009, you get a DPF (diesel particulate filter). Every once ina while it needs to go thru a cleaning cycle (regeneration). No big deal at all unless you are nearly home and approaching your exit. When it goes into regen, you hafta stay on the highway at speed for about 30-40 minutes. It does this maybe twice a year.
In 2010 and up, they have DEF (diesel exhaust fluid) in addition to DPF. So you still have the regen cycles, and also have this little tank of stuff to keep full.
Neither is a huge deal, and the highway is no longer full of smoking diesels!