[vadim]

Here is an addendum to the original DIY. It shows how to remove the parcel shelf in E92 which differs from E90.

1. Remove the seats on both sides - pull straight up at the front, they will unclip rather easily.
2. Remove the side bolsters by pulling the top towards the front (to release plasic clips) then up to release the hooks in the lower area.
3. Lower the seat backs; reach inside the trunk and remove a plastic clip (at the top) and a bolt (T40, at the bottom, right through the fold-out hook ring); bend the trunk liner at the top away from the seatbelt cover - this will expose a screw (8mm) holding the seatbelt cover in place - it needs to be undone. Do it on both sides.
4. Unclip the small plastic "airbag" covers on both roof pillar cover panels which will expose screws; undo the screws on both sides (T20).
5. Using a long screwdriver (make sure it is clean, as should be your hands so as not to leave spots on the interior - or better yet use gloves), get under the pillar cover panel at the top, then reach down along the pillar close to the glass and pry the whole panel off towards the back/center and parallel to the glass. Two round plastic clips will get undone (per side); then pull the cover along the pillar up/towards the front of the car.
6. Once the pillar cover is removed, you will see two pin clips holding the seatbelt cover to the body; remove them. Now remove both seatbelt covers.

Voila! You can now remove the parcel shelf using the OP's instructions. *** No need to remove the seatbelts in E92 ***.