I also have a 2016 LTZ with the 20 inch tires and I hate the noise they make. My car, when driving on certain roads, makes a thump, thump sound from the tires. At first I thought I had a problem with the car but the noise goes away on most roads, it seems very smooth road cause more tire noise. I only have 20K on my tires but I might replace them early as the noise drives me crazy. I have had the tires rotated and that helped a little. How can they make such loud tires today, did GM not test these before approving them for the car?