Seats
I have to say, when new, the Puma L/L2 seats were very comfortable. As pilots we had a vested interest in making sure the seats were maintained in such a state and if not doing something about it ie snagging. Many a day I spent discussing with the engineers how to get them back to there original state. More foam done the trick.
Nobody seems to have picked up on personal lumbar supports. Why not! They are a valuable item for any pilot and you can even get one designed to the shape of your back.
Made life bearable when I had one made. All the pilots with back problems had them. But you should get one before it becomes a problem.