I had a 1998 Subaru Outback that had 286,000 miles, and 16 salt-covered winters on it. Did it have rust? Sure. Was it falling apart the way ToySub1946 makes it sound like it should have? No. We washed it often enough that this wasn't an issue.
I've had my BRZ through two salt-covered winters so far, as seen above. Here is the underside after those two winters:
