1 - test fit
2 - paint
3 - install
This is of course if you are keeping you stock color. If you want to re-paint the entire thing (In this case, having a paint shop do it.) You can just install it and drive it over to the shop. It also depends on how your side skirts are going on. Obviously, if you are molding them you have to install them and then get them painted, but if you are using the double sided foam tape and screws to hold them on, then you can install, remove, paint install. Eh, it all depends!