You can use the flakes shader to render metallic flakes in a material.|
It does only produce the flake layer, to you have to add it with any other material for the surface.
You can use any specular (e.g. BA_illum_spec) as input shader for the flakes.
You can also use a shader with reflection as input shader to the flakes.
The Flake shader builds seperate layers with a few flakes.
You do not have any evaluation of your input shader in the area without flakes.
You can add multiple layers of flakes.
Only Flakes with Reflection: