[wombat7]

I've heard some different things than what has already been said. My uncle, a certified BMW mechanic, says that you want to run the engine through the whole RPM range once warm. If you do not do so, your cylinders could get negatively effected i.e. get ridges and stuff in them. If you run the vehicle throughout the whole RPM range this will not happen. You definately do not want to take it to redline when it is cold, but once the car is warm there really isn't a problem with it.