I converted my 1984 500 SEL (W126) because of the low rear end. I changed the springs, shocks and accumulators. I also gor rid of a lot of the hydraulic fluid lines and other stuff as well.
The car now sits and rides better that before although the ride improvement is for certain not caused by the conversion but due to old parts being replaced with new parts.
Before the conversion the rear end (beside sitting low) showed all signs of worned out shocks i.e low damping effect.