I don't know much about this, but I believe the brake lights are LED on the 2004 M3 and have the thing where when you press harder on the brake pedal the lights get brighter, like the thing they have on the 2004 325Ci and 330Ci. I also think there might've been a change with the shape of the rear-view mirror from the oval shape to a regular rectangular shape if you order some sorta package. Sorry couldn't be of any more help, I'm sure the other board members are a lot more knowledgeable on this subject.