Maybe my grill is a better comparison. UV light: check. Dust: check. Extreme temp changes: check, and more than a car to boot. Salt: check, there are giant cr

Maybe my grill is a better comparison. UV light: check. Dust: check. Extreme temp changes: check, and more than a car to boot. Salt: check, there are giant crystals of kosher salt all over it. You know what I think is the culprit, there must be fragments of regular steel/iron debris on roads that get kicked up and form rust spots like wet steel wool would. Rust is terribly penetrating and can easily stain SS or even porcelain. Still, a few rust spots aside, I don't think these cars will be rusting out like a 1980's Civic.