That Coupe is the worst I've seen.. Must have been an all-year-round user?
I bought mine (84400km '98) in 2002 and was REALLY petty about rustspots. I found a few small ones underneath (worst was the rear jacking points) and fixed these, then rustproofed the whole car whereever I could with thin wax. Sills, doors, lids, inner floor.
Also I never drive on salted roads (november - april here).
Seems to work!
I recognize the front strut tops, I saw small bubbles inside when I swapped to Billies. Obviously fixed right away!