Popping the door skins off I found that several of the plastic clips had crumbled, the rest were intact but loose. Also the speaker covers had cracked loose around the screw holes. Besides, they had suffered countless ski boot kicks and looked terrible.
So, get a big bag of door clips (15 in each rear door). 100x for $8.
https://www.amazon.com/gp/product/B01H6P3ZGW
The MB speaker covers go for $40/ea., more than I can justify for the evident quality. So, I found these generic speaker covers. https://www.parts-express.com/steel-mes ... k--260-418 $5/ea. The round speakers aren't a perfect fit, because one can just see the creases from the corners of the old covers. They look good IMHO. If you want something else, the mounting screws are on a 5-5/8" circle.
1) Very gently pry out the plastic trim at the forward end of the arm rest.
2) Unscrew the 3 screws that hold the arm rest. Remove it.
3) Push the trim ring around the door latch back about 1cm. It should come out easily now.
4) On many Gs you will find small black screws snugging the top of the panel to the window frame.
5) Push down the lock pin. Be careful of this area in the next step.
6) Use a plastic spatula to pop the panel off of the door.
7) Remove the old clips by twisting them such that they climb out of the holes. Look at the new ones to get an idea of how they work. Some will break, you'll have to pick the bits out of the socket.
8) Clean up the door skin and tack down the water seal on the door if needed.
9) Replace the speaker cover.
10) Reassemble in reverse order.
11) Close door, feel satisfied at the authoritative thunk.
12) Drive over rough road, enjoy the quiet.
