I was ready to buy a 2018 3500 DRW Longhorn until............ I read that for 2019 there was a change, maybe 2. The first change is the nav screen is going from the current 8.5" to a large 12" touch...
The big screen can be split in two so you have like your Nav screen at the bottom or top and your radio controls etc at the bottom. I'm ambivalent, but then again still quite a few years out from another purchase. The big difference I see, not sure if on the 3500's is the etorque feature as ones coming out soon will be "mild hybrid" and they can put the electric portion into torque apparently.