Well, call me crazy, but we bought another one. Same issues, but this is literally the only vehicle that can fit my family comfortably. The dealership did the road force balance and added the extra "sealing" to the head liner, but still the same issues. We, as a family, have just learned to deal with it. The kids keep head phones on, and I keep the music cranked up. Maybe the booming is causing me to go insane and thats why we bought another one. The 1st one we bought was a GMC Yukon XL SLT with 20" wheels. This time we bought the Chevy Suburban LTZ with 22" wheels. There is no difference in the sound, my opinion only. All the trucks have this issue. We drove numerous models from all three (Caddy, Chevy, GMC). The dealership wanted to keep trying things, but I told them NO, and we picked it back up. They did however note on the paperwork that the truck was not fixed, but that the customer wanted it back.