300D door panels

[mirage2521]

Morning Guys, I want to add some speakers to my 300D and I was considering putting them in the from door above the little map slot thing and just below the door latch. What is under the door panel in the area, and is this even worth pulling the door panel off. I hate to pull it off for no reason, I can never get them back on as perfectly as they come off. Last thing this car needs is me giving it it's first rattle after 220,000 miles rattle free. Thanks