Thanks. I use photoshop and template files provided by iRacing. The graphics were made with various selection tools, custom brushes, layer effects, generated patterns and an understanding of how to use the specmap features in the game.

I tend to start with creating graphic design elements like the blocks of color and styling separately from the car, then I take those elements and apply them to the car, taking into account the shapes of the car and how complex the template is. Then I apply logos and other details. Lastly I adapt those graphics to the specmap to make things shiny or metallic.