If your seating arrangement is similar to the W201, then I have found some peculiarities that might be affecting you if you are tall (I am not, but quite long-waisted, so I 'sit tall'). The floor of our car is high under the feet due to the unibody channeling, wiring and ventilation ductwork, thick foam, multiple carpets. This puts feet high relative to the ceiling, which is low due to the sunroof. I must adjust the seat bottom to the minimum height in back to get enough head clearance, which leaves my feet and thus knees too high relative to the posterior. I compensate by reclining the seatback more than I otherwise would, and raising the front of the seat. It works for me, but I wonder if the problems you have may be similarly related to the short distance between the floor and the ceiling, and no seat will solve that issue of posture compression.

Try removing the lowest layer of carpet with the foam padding, and any mats on top, to see if you can get more comfortable. This can be done in about a minute, but if it works for you, I don't know what is a good permanent solution.

Steve