Have read alot about that annoying harmonic sounding type vibration{drone sound} at highway speeds. Almost sounds like your driving over an area that a catapiller has sunk it tracks in the blacktop if you can relate to that. Anyway never had the problem until i installed a custom made brush guard on the truck. It probally weighs 100-125 lbs. Well guess what. I now have the drone sound and vibration. I'm thinking i probally now need better shocks as the stockers probally can't handle the extra weight. Any thoughts??????????:ro)