If model is sold under royalty free license that doesn't necessarily mean that you can use that model commercially, a lot of peoples here doesn't understand how license system works and always wrote answers in theoretical matter. For example this https://www.cgtrader.com/3d-models/car/sport/ferrari-458-italia-df3e9aff-6ea8-4ecf-abb4-b10a4e3a246c is selling under royalty free license, so what you think can you use it in commercial way without asking Ferrari for premission ? Of course you can if you have couple milions of dollars that you don't know what to do with. As far as real cars goes: Name, logo, whole design and every single part of the vehicle is protected by copyright/patent law. You can remove logos and name, but you still can/will be sued for using copyrighted/patented design without premission, altering existing design will also get you sued depending on how much of the original design is in it, there is a defined percentage how much of the original design needs to be in altered one, in order for lawsuit to get finalized.