Don't know if this will help any but I have the May 2005 issue of Car and Driver they did a test on performance meters one being the G-tech/Pro RR. This was said during a test on a Pontiac G6 " Like some of the other meters, the G-tech measures cornering grip but provides no calibration function for this feature.During our testing,we found that the lateral-g number the G-tech displayed was about 0.05 g higher than what the car was pulling according to our timing device."(they were using VBOX)