[Mr Modifier]

Re: the red wheeled mustang... Yes the red wheels look out of keeping.  I think I would spray them rust colour and then mist an overspray of silver.  Or maybe go the whole hog with the rock salt method (spray them rust colour.  When dry dip them in warm water with a drop of detergent (to break the surface tension) and immediately dip in rock salt.  Once dry spray silver.  When the paint is cured use a toothbrush to knock off the nodules of salt which will show the rust in patches)