I used GW Paints (the old kind that they used for 20-odd years) for the reds, and they airbrushed really nicely. A Blood Red base coat highlighted with Blazing Orange and Golden Yellow, Shaded with Red Gore and then some P3 Sanguine Base.
Before painting the Red, though, I painted the whole length of the car with fully shaded and highlighted white, then taped down two racing stripes, so that once I had painted the red over the tape, I could peel it up and have two racing stripes.
I wanted one thick stripe and one thin... but I should have made the thicker one even broader. The tape looked right, but once I peeled and saw it in white, I knew I wanted the thick stripe even thicker. Oh well - it's only terrain, right?
I have three more vehicles left - another Future Car with a hotrod engine, a future car police car version, and a larger, military, Future Humvee-style truck.
Windows were based with P3 Exile Blue, highlighted by adding P3 Frostbite and then white. Shadows were done with P3 Coal Black.