The left rear subframe separated from the main frame causing the car to pull to the left when braking. I had an episode where I was stopping for a traffic light and the car started fishtailing and I almost lost control of the car. Following this episode, I took the car to a mechanic who advised me that the car was unsafe to drive. My mechanic also told me that he has repaired a number of these vehicle with the same problem, and that Mercedes Benz has extended their warranty from 4 years 50,000 miles to 20 years unlimited mileage. They did the extension after someone filed a class action suit in Georgia about the problem. The vehicle is presently at a Mercedes dealer awaiting the new subframe.