I don't think selling an artist impression on Turbosquid violates any law, as it falls under their editorial usage terms, just like the other 25 billion car models sold there, which forbids any commercial use, such as video games.
The mod is a different question, whether free or not, it's not technically allowed to be published without the IP's permission. However as I said, it still doesn't justify taking the model, especially if the response mentions Turbosquid, where it's their terms that are applicable.
Also CM are not FOM or Ferrari, they are a dev studio tasked to create a video game, not the licence owners, so they shouldn't be the ones to judge, only to act in a fair way when it comes to creating/purchasing/using assets.
To quote:
"Content published with the Editorial label may only be used in an editorial manner, relating to events that are newsworthy or of public interest, and may not be used for any commercial, promotional, advertising or merchandising use. However, in certain very limited instances, you may otherwise have the rights to IP in content that is labeled Editorial. For instance, you may be the advertising agency for a brand/IP owner or you may be the brand/IP owner itself purchasing content. If that is the case, you may use the Editorial content commercially, assuming you have the rights clearance through other means. But, you must have all the intellectual property rights necessary from the IP in the content and this is usually only the case for a brand/IP owner vendor or for a brand/IP owner itself."