When I first got my car, I replaced the factory speakers. Not knowing how to remove the panel I wriped it off so hard that I cracked/stripped a lot of the plastic fasterens that go on the inside of the door panel. For a couple of months it would go it and always pop off. Then I went to a Mazda dealer, got like 10 new fasteners, installed them and not the panel doesn;t even budge. I don't even have to have any screw screwed in, the panel still doesnt come off unless U really tug on it.
Just my $.02
Just my $.02