I'm not sure I'd call the dynacorn steel upgraded, it's thicker granted but like playdough you can shape it with your fingers.
I've bought 20 project cars over the years and not once has there been any big rust surprises provided it spent it's life in a salt free environment, if I can tell someone who knows rust should have zero problems seeing it. if a trunk floor and maybe some lower rear patches and drop offs cost 10K I need to start a body shop, those are typical rust areas even in a dry climate I would bet that's about all you'd find.
I'm not trying to be argumentitive I just think if rust belt guys knew what solid west coast cars look like and that you can buy them cheaper than repop junk. I just bough a numbers matching RUST FREE real deal unrestored SS/RS 69 Camaro driver for thousands less than a tiawan shell would have cost me. if you don't believe it I can show you pictures under the car too.
If anyone finds a car in my area of travel I'd be glad to look at it for them to see if it's worth your time to see for yourself, I've been given a lot of help on this forum I'd be happy to return some. just watch craigslist they come up all the time.
If it costs me $2000 every time I travel to look at a car I might want to buy; I might as well fix mine.
What I've noticed, is that many cars are advertised as Oklahoma/ Texas, etc cars.
Bottom line , is that over the last 40-50 years these cars have been almost anywhere but those places. The guys drag them in from where ever they are buying them and put them up for sale. I have driven down that road and seen it first hand. There is practically a place that sells car almost every mile or so, and a place that sells trailers to take the new project home, every 10 miles.
My car was solid and garage kept for the last 20 plus years. The metal work that was done is representative of what was available at that time. There were no holes in the roof line showing, but my body guy just knows how to find things. I just can't believe the rust goes so deep into the structure of the car.
If I had good contacts for doing a car search, things might be different. But the way I see it, it's buyer beware, there is rust in there somewhere.