Since I haven't seen any mention of speedometer calibration since the 1st or 2nd page of this thread I'm curious to know if anyone else recoded their speedometer with VCDS or OBD11? I chose option 6, which according to the measured values was expecting a tire size of 2323mm. This was the closest to what tires I chose vs how it came from the factory with option 3 which measured values showed as 2205mm. Several of the other options were not permissible even with security access enabled the system just wouldn't accept the coding changes. I then used GPS on both Android and iPhone to confirm speed vs actual speed under measured values (in kph from the VCDS) and they all checked out. I think I'm comfortable with trusting the speedometer readout now and calling it within less than 0.5% of actual speed. I did this at various speeds according to my local roads 25mph, 35mph, 45mph, 55mph, and 70mph and had my passenger track and record the speeds.