this is the best thing that i ever did to my 560sel, which i purchased in the fourth quarter of 1986.
i did it about 30,000 miles ago[car now has 250,000 miles. we used two of the o.e. pads. initially, i felt that the seat was too plump. after 30,000 miles, my bottom has benefitted.
these seats are already better than normal as they were the orthopedic options.
in closing, having driven lots of cars over the years, at least through the w126 sedans, daimler benz seats were the best in the business.
my guess is that this is no longer the story.