The side carpet is easy to do. The black fasteners (they have a mercedes emblem in the middle!) pop out and are reusable. All you need is a small screwdriver to pull back the part with the emblem (it doesn't come out completely), once this is pulled out the entire fastener can be removed.

Sorry if this sounds confusing, but its really simple once you get back there. Once all the fasteners are out you can pull the carpet pieces out.