Look under the car in the area of the rear jack point. There's a salt shaker shaped flange, round end to the rear, about 10" long by 6" wide. Above the round end is the rear subframe mount. One per side. As the subframe mount collapses, that side of the car sits lower to the ground. If one side collapses more than the other, the car lists.

I'll try to post some pics but I can never balance image resolution and the limits of the attachment file size to the point that I post any useful pictures.

Sixto
91 300SE
87 300SDL
83 300SD