Because of the original question being somewhat vague as user @max_power998 pointed out, and that this question seems to be somewhat "general", I decided to move this topic from "Donut Mod" to "Mod Requests".
If this is a question or a request from Donut Mod, I don't really see it working. Any new cars being added to Donut Mod will either be taken from entirely different games, or inspired by scenes from the television show. Skulls would be an odd addition with no clear source, but it'd make for an a-okay standalone mod. However, please be a bit more specific in your question with what car you'd like. Hopefully somebody will take this request up.