Obviously a time to clear a few things up. The only time licensing generally becomes an issue with car models is when you try to use a companies logo's or trademarks in a way that would offend or directly compete with that company. If there were an issue of using cars in any art form many t-shirt vendors would go out of business as would many artists that sell auto art prints and such. Not to mention many movie companies that use classic cars. There has been a long term precident set already and there are numerous 3d models available without a peep. In the Computer games industry (where I work) licensing is obtained mainly because the said cars are to be represented as accurate representation not only in looks but driving characteristics where if not accurate that would certainly offend an auto maker. Some games, Tokyo Extreme Racer Series for example, use quite accurate car models but give them slightly differen't names and logos. With that said I have still started making the logos and trim on my models able to be turned off for end users that are nervous about law suits. For instance if you are concerned about using the 57' T-bird for some odd reason just go into the hierarchy editor and turn off the trim.