this is a bit childish but how about glow cars.In the night it glows but in the morning it is normal.
Hmm...what if that was like a reward for mastering a specific car? For example, let's say the Gavril Grand Marshall became my favorite car. I would race it a lot and complete various challenges to increase its level and unlock more parts and stuff. After you've ranked a car up to the maximum level, you could unlock "special paints," like silver chrome, glow-in-the-dark, or pearlescent. That way, you could brag about mastering a specific car by showcasing the special paint. (imported from here) (imported from here)
