If I recall correctly, the exhaust systems are stainless steel and should not need any further protection, even if there are rust spots on it, but as far as the underbody, paint might be better than an undercoating, as the thick rubbery spray has been shown to trap moisture, promoting rust. The newer vehicles are better protected from rust than ever before, and I would be surprised if rust became a problem. Some parts are expected to have a (protective) coating of rust. Hope this helps, but I know that salt is a big problem up north, here in Florida it's just on the table.


