I would not consider Missouri "rust belt", and I have lived here all my life. We get winter weather, but not a lot of it, and it is usually in short spans. When it snows here, it is a 24 hr thing typically. So while they do treat the roads, it is not so bad that you cannot over come the effects to your car for the most part.
Oddly enough, Illinois is MUCH worse. Even people in the metro east of STL, who are at the same latitude as those of us in central Missouri, will have more rust problems. I think that is just because the state of Illinois is more likely to salt the dickens out of their roads, all over the state, not just Chicagoland.
The cars that rust bad here are the domestic pickups (those are really the worst), lots of GM vehicles like J-bodies and N-bodies, Nissans, Subarus (Subarus must be made out of some of the cheapest metal on the planet), Chrysler minivans, and to some extent some of the older Fords like the Taurus. We see a lot of GM/Ford/Chrysler brake line failures, too.
But Volkswagens, at least in the modern era, are generally limited to the foam-block-induced fender rust on the diesel A4s and some B5s mostly. My Golf has some rocker rust starting just on the driver's side, but I think that was spurred on by a past accident by the previous owner that was poorly fixed, as the fender had been pushed back and kinked the body and they just slapped a new fender on. Because you can see the rust started in earnest right at the kink and allowed debris and water to get into the body cavity. The passenger side is still like new.
But as far as nuts and bolts and underbody fasteners are concerned, it is not much of a problem here. I do encounter a lot of seized tie rod toe adjusters on VAG products, even if they do not look at all rusty, but that has always been that way.
So, to me, a car that has spent all its live in Nevada certainly looks better than one that has spent all its life here, but something that has spent all its life in Cleveland is MUCH much worse.
