Northern X5s - Issues to look for?

[MotoLinz]

I'm going to guess that rust on the calipers is not a good sign, but I've spent most of my years in Florida, so I know basically nothing about wear and tear on cars from north of the Mason-Dixon. I do know that winter salt and sludge can take its toll and turn a shiny ride into a rust bucket, so what specifics should I look for on X5s that have spent their little lives in colder climates?

(I may actually get a new car by the time I'm on Medicare. )