I only had M3 a couple of weeks when on freeway I actually saw the tennis ball sized rock bounce off the road hit the passenger side of screen and over the top of the car around 70kph, the noise was loud, I felt for sure a new screen, I pulled over and inspected, I thought that was lucky only a tiny chip so I bought the repair kit and got home to DIY but as I cleaned the glass there was no chip just a bit of sand off the rock, lucky or what.
next day I got screen cover added