Well just got back from our Thanksgiving trip to Calif. (4995 total miles) Truck did real well with no comfort issues, MPG averages were a low of 22 and a high of 30. Speeds ranged from 65 to 95 MPH (all interstate). Did have one issue though, had a DIC prompt saying "DEF quality poor" and had it go into "limp" mode at 65mph and then down to 55mph (man did I piss off some truck drivers on I-70, Sorry to all of you!) until I could locate a Chevy dealer in Moab Utah named Crump-Reese Chev/Ford/Buick/Jeep (a BIG shout out to Jordan and the guy's!!). They got me in right a way and plugged-in and ran diagnostics and tests for 1 1/2 hrs. and could not find an issue or duplicate the problem, cleared out a couple of codes and sent us on our way with no further issues so time will tell. If any of you ever get the above mentioned prompt, find a dealer right a way because if the vehicle goes into limp mode it will reduce speed all the way down to 5mph. I think that if the conditions are lined up just right and you are on the Interstate some where and your speed is reduced just to keep pollutants out of the air, it can put you and others in a dangerous situation.