Attached Link: Real World Metals

I bought the Real World Metal Carrara Shaders by litst Without giving away too much, I hope, I can tell you he used a bitmap of noise in the hightlight ande the reflection channel. That gives a subtle 'metallic' effect. Maybe more experimenting in the reflection channel helps. And maybe there should be more to reflect too, in a picture like the one you show. The thing with car paint is the transparant layer on top. That creates something like a 'freshnel'-type effect on how the color looks. Maybe Digital Carver's Guild Shaders Ops can be of help too. It helps to have a shader collection like the one from litst ( a visit to www.3dshaders.com can be equally rewarding ), because you can tear them apart and look how they do it. But you have to pay some cash.