My front seat was a tad bit too comfortable, could feel the bottom. Could be that I'm a bit heavy set or that the previous owner was... Anyways decided to replace the foam. Removed the seat in full (6 bolts) and took it apart. Very easy to do and it was only necessary to remove the front part of the cloth. The foam-guy was then able to cut the old foam and use bottom and top part only replacing the "mid-foam" to a better quality. He also split the mid-foam and reinserted the steel parts, not sure what it looks like. Here are some pictures of the full job. Didn't take any pictures after re-mounting in the car. Don't know why.
