Doesn't anyone know what a TM before they register a domain? It seems that every domain has a TM issue. Come up with an idea and contact Lexus and see if they will give you permission. Or just sell the domain to an unaware domainer.
There are certain cases where trademark holders have taken people to court and lost their case. A good example of this is Paypalsucks.com. Alot of laws are very interuptive. Especially trademark laws. "CNN reports that a man's website, http://www.bosleymedical.com, criticizing the Bosely Medical Institute does not infringe the institute's copyright on its name. The man's attorney is quoted as saying that the court's decision 'is an important victory for free speech on the Internet. It makes clear that consumers can use a trade name for a company they want to criticize.'