I have a 2017 S model and i am having an intermittent vibration while on the interstate (70mph+) it ranges from mild to severe. i have taken it to the local dealer and they say that everything was checked ( tire balance, drive train, steering and front end ) and found nothing wrong. I do understand that the vehicle has a stiffer ride, but i have owned 2 sports cars that were far stiffer and did not have this issue. I am really concerned about this and was just wondering if anyone else is having the same issue. I purchased the vehicle for me and my wife to make road trips in and other than the vibration i love the vehicle. it is bad enough that my wife will not drive the vehicle!