I'm most concerned with the inner rocker panel, which I think might be part of the floor pan, it's the panel that the seat belt bolts into. I also watched this video where this guy used rivets because he was afraid of warping the thin metal. You make a good point about the corrosion, I was just curious why everyone uses rivets instead of screws, there's almost definitely a good reason.

__________________
1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition