Two major issues with the R129's in the biodegradable wiring harnesses in the early to mid 90's cars, any sign of cracking of the insulation the harness should be replaced immediately as if it shorts out the wrong way it can take the injection control module with it.
The other biggest issue are those cars fitted with the electro hydraulic suspensions, ie some, maybe all US and Australian delivered V8's and probably all V12 sl's, overly complicated and very, very expensive to have repaired at the major big city dealers and just about impossible else where.
Last Christmas holidays I replaced the whole system with conventional gas shocks, springs and rubbers, "Shoey" might be able to tell the difference I can't
I would not recommend anyone try replacing the springs, high risk of them jumping out of the spring compressor, best leave that to a professional