if you want the paint to stand up to rocks and gravel look into DuPont Imron 5000. Its tuff as hell and easy to shoot. No it does not come in a rattle can but it will out live your XJ.
FACT: Bright hot pink paint is the most durable paint. The car companies don't use it because they want your car to rust a few weeks after the warranty runs out.
Use it on my axles, skid plates, links, cage, doors, hood, etc. Basically I just spray everything on my jeep with it, makes touch up easy with no masking.