This is a timely thread. Yesterday I saw an XF on a dealer lot, about 14k miles. I briefly dropped down to look at the underbody from the rear, and saw a fair amount of corrosion on the exhaust system.

I'm a Californian; I don't typically see a lot of underbody corrosion. (My own XF w/33k miles is much cleaner underneath.) How serious a problem is it? Ignore-and-all-will-be-well-for-many-years? Or take-it-to-a-body-shop-immediately! Or somewhere in between?