I hate getting in one of these discussions. I watch people blow gobs of money ruining the handling of MBs. Its probably possible to improve, to taste, the handling of these cars but the normal attempts have more to do with looks and the standard 17 year old MB will be helped a whole lot more by the proper maintenance of the suspenision that MB laid under it.
Chances are good that the car in question will gain more from a good alignment and a set of high speed Michelins than all the bucks you can spend elsewhere. Shocks, springs, I don't care if it sat all those years, its still old. Freshen up what you got and get to know it before you ruin it.
Bosch Master, ASE Master, L1
33 years MB technician