Man, that's one sad picture! ...
I live in Olds,Alberta Canada (Prairies) so of course I've never seen the effects of salt-water corrosion.
They do put salt on our highways after a freezing rain, etc. and we whine about that. The salt attacks suspension and lower-body sheet metal over the course of 10 or 20 years or so. But to see a 2005 Grand Prix looking like that is shocking!
Is all of this caused by the flood, or was some of it caused previously by high humidity and/or "sea air"?
If I get time tomorrow, I'll post the same shot of my 1998 GTP (3800 Supercharged) engine compartment for comparison.
PS ... 100,000 miles on a 3.8 is "just getting broken in" according to what I've been told.