Agreed on the bolster. I also drive a GLC from time to time and I look forward to getting back into the Mazda. I actually enjoy the seat firmness.I just did a +3500 mile, 500 miles a day, road trip in my new 2021 GTR. No comfort issues at all. The manual explains how to adjust them, but I just set them up how I usually do. I do wish they had a bit more bolster on the seat bottom. I’m 5’9” 165lbs.