Hey Jim, I did a similar move from a 2015 Tahoe LTZ to a 2017 Yukon Denali. The 2017 Denali definitely has the softer seats than the 2015 as well as a more compliant ride. They are using the same Bridgestone tires (on 22"). Neither of these had the boom/buffeting plague. I don't know if the 2017 Chevy LTZ has the softer seats/ride as I didn't drive one. A GMC Yukon Denali priced out cheaper than the LTZ?? I felt my LTZ rode like a lumber wagon...took it a few times to have them see if there was any update available to soften the MRC. Obviously, GM listened, because the 2017 is dramatically different.