It looks real good To get the materials go to steam --> library --> tools and download Automation workshop tool. Once it finishes downloading, right click and go to show local content.
There you will have the exporter, a PSD file for the thumbnail and a sample 3ds file where you can get the materials.
EDIT (step by step)
To get the materials, in 3ds, bring the material editor, in mode change to Slate material editor, then in MATERIAL/MAP BROWSER click the black arrow and select open material library, search for the 3ds file you just downloaded and open it. It should bring quite a lot of materials. Look 13 default sub... and drag it to the view1 window. Now click apply material to selection. Go back to the regular material editor and click get material with your mesh selected and there you go, you will have the materials ready for use. Now, in poly mode you can change the material ID to get the different materials.
Here's a spreadsheet made by daffyflyer to help you calculate Cd and lift values https://www.dropbox.com/s/0fpm41n4if112d3/Aero.xlsx?dl=0 (it's a more advanced version that the one in the automation workshop tool). You just put the height, the width, ground clearance, aspiration type, year, power in Kw and Cd. of the original model, and it will substact the cooling giving you a Cd value for the body, If you can't find a Cd for that car, just use this http://hpwizard.com/aerodynamics.html to get a cd value and then use it in the calculator, it works really nicely.