Removing the door skin is not the easiest of tasks. smart have engineered the it to be one of the primary components of the door. A lot of components attach (or pass through) it and these must be removed in order to free the skin. Please note - the coupé and cabrio skins are different! In order to complete this removal, you will need a Torx bit set.
Start by ensuring the window is up. Remove the wing mirrors.
Completely free the door handle by loosening the Torx bolt on the back.
Remove the door pocket.
If you have electric wing mirrors, remove the switch. It simply pulls out of its base and unplugs. Remove the door handle to 'unlock' the door card.
Pull where shown and the door card will become free.
Pull out the door hinge cable channel.
Free the door wiring from it's clips.
Unplug all three door lock connectors, the window motor and the window button. It is easier to push the window button out from behind in order to disconnect it.
Feed the entire loom through where it enters the door skin from the hinge.
Undo all 8 screws that hold the skin to the door frame.
Undo the two bolts that hold the skin to the door lock.
There is one final screw which holds the interior door handle to the door frame. This screw can be accessed through a small hole on the outer side. Take care not to loose the screw into the door frame.
The skin will now separate from the frame but will not come fully free.
The door handle operates a cable that releases the door mechanism. Another person would be useful at this point. Whilst one person holds down the actuator on the door lock, there will be enough slack in the cable for the other person to free the cable stop from the door handle. In order to do this, side the cable bend away from the handle assembly. Try to be careful so as not to break off any of the clips.
This shows the orientation of the bend in relation to the handle.
The door skin is now totally free, revealing a very bare looking door.
Installation is reverse of removal.