Check it out for yourself, it's up on the material database: http://www.indigorenderer.com/materials/materials/1390
It's a fairly crazy material and I'm not a 100 % sure of all the details in there myself, but I'll try to explain:
There's one material called "base".
This material is a simple neutral specular phong with Exponent @ 60.
Then there's another material called "flakes".
This is also a neutrally coloured specular material, but with exponent value 100000. In the Normal Map slot of this material, there are 10 lines of code with seemingly random values that Ono must have tested his way to. The first line contains scale - probably the scale of the random normal map noise the rest of the code describes. The second one, alpha2 controls the roughness, and I found that a lower value in this parameter gives you more subtle flakes more concentrated to the highlight area, not appearing randomly in the other parts of the paint.
The material speckled carpaint substrate
is a blend between these two materials. The blend map is also a script, with a more simple gridnoise function controlling the blend. The blend doesn't have any greys, because the line "if r > 0.7 then 1.0 else 0.0" means that the parts of the grid noise with brightness value over 0.7 gets brightness 1.0, and the parts of the grid noise with brightness less than 0.7 gets brightness 0. So every part of this blended substrate is either the material "base" OR the material "flakes".
On top of all this is a coating.
This has IOR 1.6, thickness 1000 (micrometers?) and coloured absorption. The colour that you use for this absorption is what you use to set the colour for the whole carpaint. A cyan colour gave me this red carpaint for example.
What I also added to this coating is a small scale and amplitude fbm noise in the bump slot of the coating. This gives a nice organic orange peel effect to the clear coat, some imperfection.