I just bought a 2014 Silverado, with the former "extended" cab setup, 5.3 l engine,18 inch wheels, Goodyear tires. I'm thinking I should have run away...when I first drove the vehicle, on the interstate, I said out loud to the salesman and my wife "it has a vibration." Thinking it was just an unbalanced tire, I went ahead and purchased the truck. Now, the dealer has force balanced all the tires, which did not solve the problem. The service manager has agreed that there is a vibration, but he and a technician drove other trucks of the same configuration under the same circumstances - about 65 to 72 mph - and they all had the same vibration. I am not happy with Chevrolet...These vehicles are advertised as being quiet and so forth...not so. I am not a happy camper. I won't be able to speak again with the dealer until next week. A poor vehicle. I will pursue my options now, with the things I've seen here.