I am of the opinion that Mercedes springs are like any other type of spring. In time they lose their ability to recoil or their strength. I have a 1983 300D Turbo and I am going to replace all the coil springs and the bushings. My car rides a little low in the back and I changed all four shocks not too long ago. I am going to try to get larger bushings for the rear to increase the ride height in the rear. I think if you change the springs, you will definitely notice and feel the difference. Be very careful if you change them. The best way to perform this operation is to rent a spring compressor tool. It cuts down removal and installation time ten fold. You don't have to drop the front or rear end at all. There are some places that rent the tool. I bought one from the dealer, but it was almost $800.00 so you're better off renting. However, I cannot stress this enough, be very careful when dealing with springs under tension.