Funny, this one has the same irritating buzzing sound when it crosses over 6000rpm. I had it fixed by Porsche, but it took them some time to find the spot which causes the buzzing sound.
Nice car. it's not too dark inside without glass openroof and alcantara (black / grey) ? I'm not sure to leave your ID on the car + recording high speed in limited area is good for your driving licence :)