Well, I suppose it is all matter of personal preference, but I have had excellent results with HDs in a wide variety of applications over the years. I find MBs of that vintage to be rather 'soft' by modern standards.
HDs are firm, but not harsh (IMHO), and consistently a good match for stock springs, so one does not lose any travel. I tried a similar SL with them once, and thought the ride was nice. Did not do a 'before and after' though.
Best of luck.
1986 300E 5-Speed 240k mi.