During the trip to Germany we went so the limiter hit in about 20-30 times maybe during the trip. The limiter is "softer" when going in 6th gear than when you hit the limiter in 5th gear. Also, it indicated 270 km/h om the M5 speedometer and 265 km/h on the M3 speedometer. Then the speed on the M3 board computer (an unlocked function of the on board computer) was 256 km/h or sometimes 257 km/h.
Sometimes the M5 was going faster, sometimes the M3 were going faster.
If you see on the preview I'm chasing a E39 M5 with 260 km/h on the speedometer and the M5 was about to brake, so I had too get rid of the camera quite fast. The difficult part wasn't to drive fast, it was to take a good picture in the same time.
After we removed the speedlimiter on the M5's there was of course no chance for me to keep up.
Also, we went with the Nowack M5 over 300 km/h on the tacho with 5 people in the car without any problems.