Long time multi Mercedes owner and also currently have a 2017 SL 450. Traded my 2014 CLS, for new 2019 CLS, Dec 2018. Always appreciated the hard seat design MB is noted for. However, my leg was going numb and my rear end area experienced continuous discomfort. The dealer replaced the seat, but same issue. The service manager investigated and explained there is no padding in the back of the bottom cushion, that your sitting on the stretched leather. Since the design of the seat has the thighs working up and the sides of the seat raised, your in a hole. Spoke to Mercedes customer service and they said, nothing else could be done, but offered no explanation, why the seat lacked padding typical of any other Mercedes. I have tried 4 different seat cushions, but none can completely resolve the issue.