My driver's side GTA door panel is falling apart and no one makes a repro. And I need to take it off again. This really sucks.

 

I'm guessing your black plastic top rail is torn off the cardboard panel? If that's the case, I've had good luck using aluminum (not regular gray) duct tape to hold them together from the backside, which will hold the panel together long enough to get it on the car, if you're careful with it. Once it's on the car, you won't be able to tell as both the top rail and cardboard panel have their own clips that hold them on the door.

Works nicely as the aluminum tape is made for high temps, and doesn't leave any residue like regular duct tape does. You'll have to redo it every time you take the door panels off, but it's the best solution I've found. I've had each of my door panels off probably 15-20 times over the past 4 years.

 

I have a roll of that aluminum tape. Never thought of that.
My problem is the metal brackets on the backside that hold the plastic clips. They tear the chip board every time I remove the door panel and I have to glue them back on.

 

I have the same issue. Last time around, I used JB Weld to reattach the metal brackets to the cardboard. I haven’t removed the panels since then, so I can’t confirm if it worked, but it seems to be pretty rigid.

 

Do u not have a tool for removing the clips from the door?

 

Dude, I've got so many tools I can open a store.