First of all I want to excuse my poor english, because it's very hard for me to find the right words to explain something. ;)

Before we Start:

The first thing to do is to create a simple scene to make our test.

We create a plane (50*50) and a torus sitting on it.

Plane: we assign a dafault Lambert material.

Torus: we assign a temporary Phong material.

Now just delete the Infinit Light and creat a spot light pointing at the Torus:

The last thing to do is to create an Image Based Lighting Pass, so we can have good reflexions. Choose an HDRI file with interresting contrast.
I render region option, put ON the Final Gathering and the Preview Final Gathering. Let the other option be default.

Material:

Let's focus on the material now. Just open RenderTree (shortcut "7") and select the Torus.

Select : Nodes/Mixers/Mix 2 colors.
Do like shown on the picture below.

We're gonna rename Phong4 to Reflection_M. This node will bring the specular and the reflection to our material.
Reflection_M:
Diffuse color: 0,0,0
Ambiant: 0,0,0
Specular: decay: 5 (this figure because we want to have a wide specular)

Now we connect a Mix_2colors to the specular and then connect 2 Phong nodes, one for each color. See the picture. That will give us a strong and small specular (600) and a wide and soft (18,436).

Now connect an Incidence node to reflectivity and set to
Surface/Camera
Bias : 0,62
Gain: 0,285

Put an Intensity node between the Incidence and Reflectivity entry like that.

The Incidence node give us the gradient to drive reflectivity.

The first part of the Material is done, Ouf!!! ;)

Now we're gonna work on the color car. So we connect a Blinn Node to the the base color of the first Mix_2colors.

In the RenderTree, go to Nodes/Mixers and select Gradient.
Why choosing this one and not the one in texture, because we don't want to drive it with a projection. The one we choose will be drived by an incidence node, more intersting for us now.
Make a gradient color like in the picture, darker to lighter color. This color will give general color of your car. Don't forget that you must be in the same spectral color.
Exemple:
Color 1: 0,067 0,000 0,000
Color 2: 0,071 0,000 0,000
Color 3: 0,631 0,115 0,000
Don't forget to switch to linear too.

And then put an Incidence node to the input of the Gradient node.
Set it like in the picture.

Now something is missing, the metallic effect. We're gonna do it by using a 3d_fractale that we connect to the weignt of a Mix_2color new node. Just do like in the picture. Don't forget the Vector_State that drive our fractal.

To achive the metallic effect, we must tweak the Blinn's specular till you get the effect you want.
For those who don't want to wait, there's a preset to download at this adress
http://www.xsibase.com/tools/shaders.php?detail=951

Hope this tutorial helps, and just excuse my poor english ;)