[vladinecko]

think of it as buying a pair of new shoes. you gotta walk careful in them because if you start running a marathon right off the bat, they will hurt your feet really bad. you gotta wear them down a little, make 'em loose, stretched and adjusted to be able comfortably walk in them.

same with the engine, there are some moving internal parts that are rubbing against other parts so you gotta take it easy at the beginning to give those parts time to adjust and smooth out. if you push it too hard during break-in period, you risk making things way too loose.

i think it's also some kind extended testing period where they're basically saying, if nothing major happens to the engine/breaks etc. in the first 1200 miles, it is safe to assume that there are no significant manufacturer defects in the car and therefore you can feel free to push it to the limits.