I really dislike having to remove my upper door panels. The fir trees are pain. Every time I remove them, one of fir trees is inevitably ripped out of the panel. So I was thinking, what if you glue magnets to the door panel around were the fir trees use to be and use them to keep the panels on. A magnet should adhere to the black metal bracket the fir trees stick into. Here is some magnets I found on eBay. There pretty much have the same diameter as a fir tree. The three millimeters of thickness should be enough to make contact.
Has anybody else done this? This would literally turn the job of removing the upper door panel into a 2 second task.