How do you change the spark plug gaskets in the valve cover on a 1.6L 200sx?

From what I've read the gaskets surrounding the plugs are not user serviceable. You can call a Nissan dealership and ask for someone in the service department. They are usually nice people and can answer that for you. If they are available the Nissan parts department can get them for you. My local Nissan dealership has helped me out a lot.