Corroding Brakes

#1

I live in NY and recently bought a 2006 Subaru Legacy wagon in PA. When I bought it, there was some slight surface rust on the rear brake rotors - just the section between the ‘disc’ and the wheel. After driving in this winter, on our salt covered roads, I am seeing surface corrosion on the ‘disc’ section as well, and even some on the calipers. I understand that salt will do this, having lived here all my life, but why is it happening so quickly, and why do I not see this on other Legacy’s that I have looked at? What can I do to prevent it? As the wheels are 5 star alloys, you can see much of the brakes, and it loooks unsightly (plus it obviously does not bode well for brake performance down the road). Lastly, I have read numerous opinions online about car washes (at home, touchless, automatic with cloth/brushes, and wand). Aside from doing it myself (which is touch as I live in an urban area), what is the safest way to wash it and not harm the finish?

#2

Ahhh yes, the fameous DOUBLE POST.