I don't know about a break in - but I can tell you that my brakes were pretty sensitive when I bought my car and still are exactly the same now, after approx. 6500 miles. I don't mean overly sensitive - I would say very responsive - like you said, just a light touch brings the car to a complete stop. It just took a little getting used to. My other car is a big old Plymouth van, so compared to that they are pretty sensitive.