Thanks for your kind replies. I am glad that you like my track layout and cars. I used acrylic colors from Games Workshop that I normally use to paint my Warhammer miniatures with. After painting I used a glossy clearcoat to fix the colors.
Yes, that's possible, but if you start them from the regular starting position then they will crash each other all the time as they all try to drive in the middle of the track. When using more than one pace car I would recommend to start them from completely different positions on the track.