Hey georgibg,
to paint a car you need the following:
- A mapped car shape in .psd file
- A painting program like Adobe Photoshop (no freeware) or GIMP (freeware and not very much less good)
- ZModeler (a program to view your shape in 3D and get the textures onto it)
- ZAZ tools
Then do the following steps:
1. Download the texture map of a car shape
2. Open ZModeler and then open the .z3d file of the car shape in it and compare which parts of the texture map correspond with which part of the car shape
3. Paint the texture map files (.psd files) with Photoshop or GIMP and safe the texture map as .tga file
4. In ZModeler, press E to open the material editor. Assign the two new .tga files to your shape and have a look if it works fine. If not, repeat step 3
5. When you're fine with the result, open SlimTex from ZAZ tools. Select Batch TGA to TEX and convert the files in .tex files.
6. Rename the .tex files to the name of the files you want to overwrite and if this car uses another shape than the earlier one, do the same with the shape files (GP4 lod files)
That's it. If you've done everything correctly, the new car will be in your game.
I hope this helps.
GPGSL : Team Owner of 'Maverick Track Performance' (MTP)