Well my 94 sales catalog lists a "Sportline seating" option for the W124, which was standard on the E500. The option included different front seats and two-place rear seating with a center console. The seats are aggressively bolstered but I can see that the basic frame and springs might be the same. You definately sit "in" rather than "on" the seats.

Good luck with your search.

Dean Albrecht
94 E500