Not sure about the back but the bottom is 2 elements. 1 is attached to the foam and the other attached to the leather. So if the replace both, you get a new seat except for the metal frame. The only thing I don't like is on the new seat bottom leather is it is not tucked in under the front lip. The tech and I had an argument regarding why the leather wasn't tucked under the lip in the front and he kept telling me that is the way the new seats are coming in. If true it looks like Chrysler is trying to save money on all the new seats. Mine has been replaced 3 times, (every winter when I try the heater in doesn't work) POOR DESIGN!!!
Thinking about going to Mercedes and see if they know anything.