80 grit leaves a lot of scratches but does cut thru the layers of paint and bondo pretty briskly.

That will work "but!" take it easy! that tool and the speed it spins will cause enough heat to warp the sheet metal and grind the edges thin in the blink of an eye.

The factory finish is hard as nails. I would break the finish with a 36 grit then use stripper on the big flat surfaces. Once you have scraped off the bulk of the finish then continue sanding carefully to finish the removal. Avoid getting stripper in the seams. It will lay dormant until paint and primer solvents reactivate it.