My 2016 GL 350 has a vibration that continues to get worse over time. I had the exact same problem with my 2012 GL 350. After several tire changes, road force balances, highway drives with technicians I changed into the 2016 model only to experience the same problem but even worse. It is always the same response from dealership that it is tire related. I use the MB tires they sell and rims and constantly the same issue. I have 72000km on my 2016 and it is sometimes so bad we feel sick at speeds of 116-138 km on highway. Winter tires are put on and same issue. This is not a tire issue but a issue with the truck. I have test driven the GLS 450 and it seems to be much smoother. We have a GL 550 with a slight vibration but nothing like the deisel truck. Now Dealing with new tires and highway road tests only be told it’s normal or we can’t fix it. Unacceptable for a 96k truck. Anyone else have this issue? Truck gives me anxiety to get into it and makes me want to cry thinking of uncomfortable highway speeds.