Link to finished Original : [link]
Here is the process for those interested.
1: Simple blocked in shapes with simple gradients.
2: Basic paint block in of the car and some background elements to get a feel of it all and simple textures
4: Lasso tool cleanup using the perspective that was plotted
5: After elements are cleaned up some i started applying diffuse colors with simple Light and Dark Gradients of the diffuse colors.
6: Began placing the reflective qualities of the materials
7: Further reflection details and started to make the glass transparent and detailed background
8: Specular highlights and bloom along with other subtle light effects
9: Depth of field, sun glow, noise, color and saturation adjustments
Basically followed the process a 3D render goes through. Diffuse color > Light and shadow > Reflections > Specular > FX