Try mixing some primer in with the color.
That will give you a flat, faded look.
Try variation on that idea.
Spray it with lacquer, dry, just buff the bottom sections.
Use your imagination.
When I lived in San Diego, to try to match the faded look , I would add a little more silver or gray to the top surfaces, kind of like the sun had eaten at the paint.
Experiment! You can't go wrong with a used, faded, clapped out look.
Spray dry and at higher pressure.
A little red oxide primer just splattered on around the lower edges could look like rust.
Let me drive your vehicle for one winter here in the Mpls./St Paul area would do it for sure
Just my .02
CCDually