If you saw how cars were tested directly off the assembly line you wouldn't worry about break in. Like stated before about the guy who works or worked at Lexus, when they come off the line they have to put them through a quick short test track that usually includes some harsh testing to ensure the car is ok. I'm not saying every single car is put through this but some get the **** beat out of them for that first mile or two on the test track.
Here is the one in the quick test tracks in Smyrna where the Altima is built.
