Had a car come in complaining about the seat back digging into their back. Car has 260xxx kms/161xxx miles(not that it matters a lot) Sure enough the foam is split and pushed back. Needs a new piece of foam aka new seat. I don't tear seats apart everyday but these ones seem pretty cheap there's only one spring going side to side on the back rest and it's near the bottom. So the entire center of the seat is just a piece of foam that's wrapped around the sides to the rear and glued.
I have good news though, they're easy to tear apart.