not touched the fronts yet but the rears are a piece of cake.
fold the rear seats down and if you look there are i think 4 screws in total, maybe 5.
2 underneath the shelf and 1 beneath a cap were the seat was sat wen in position and the last and easiest to see should be looking at you wen u stand behind the car with the boot open, it has a cap over too, just pop these off with a flat driver.
shelf might need a lil tap from underneath but will probably be free as soon as the screws are out. speakers are plugged into the car so unplug it b4 you walk away with the shelf!
as for the doors, just go around the door card and remove the screwa, just make sure you can put them all back in the same place, id imagine the card also needs lifting in a certain direction as its prob hooked on somehow but as ive neva touched the mera's i cant tell you
good luck