I have a G-Tech Pro with updated software, it didn't work too well. They say it is accurate to the 100th of a second. I brought it out to the track with me and it was .2s faster than the time on the clock. I know they have issues with cars that are high reving. I was in a S2000 with a 9000rpm redline. This made many of the other functions on the G-Tech useless (hp, torque, etc.) The new software was suppose to correct this problem, but I didn't see a difference. This was a year ago, but I'll try it out on my ITR and I can give an update.