Thats wut i do hate is that when you do have to remove them for any reason as for adding side skirts they do depending on the term they have been on the car wear the paint on the edges of the surface it overlaps. Some are nice sum are not, they do keep that big splash that most people see on the sides of their car when driving in wet weather tho.Rust??? If you drive in lots snow , they will maybe keep it to a minimum as for teh snow and salt and wutever else will collect up on the splash gaurd and not fly all over and cligng to the sides of the undercarriage where most rust forms.