First off, there is a big difference between a copy right, and a trademark. Second a warranty is just a guarantee against defects, etc. Trademarks expire, just ask the drug companys, well in is no different in the car business, this is why you have companys like "year one" who can basically give you a complete car from the 70's. Second, once you alter you car you have effectively violated the trademark of Ford according to their point of view, as you have changed something that has their name, and symbol on it, which from a legal stand point alters the trademark. As for a gray area... How do you think lawyers make a living? The Law is nothing more then one big gray area. So all I can say is F$$k'em if they don't like it!