Other than shocks, what would make a car ride rough. Maybe because my other car is a Jaguar, which is very smooth, my 73 450sl seems to ride rather bumpy. It's got Bilstein HD shocks, which appear to be the right application. It's only got 112,000 miles, so I can't imagine the springs are bad. Some people have said to use Boge, and others have said not to. I also understand there is no Bilstein Comfort shock for the 107 sl. When I have the tires pressured up to the right pressures, and the road isn't smooth, it can be a bumpy ride. Other than that, though, the suspension is great. The car corners flatter than any car I've ever had.