just went out and did a few runs with my gtech..i averaged 6.3-6.4 0-60, and 14.82-14.88 1/4 mile. ON my last run I did a 6.15 0-60, and 14.69 1/4.. This was with everything out of my trunk, temperature probably 75, all mods listed below, except i was running stock rims,tires...

 

bump

 

I'm not going to say that is totally accurate, but from my experience with mine I can tell you that the 1/4 times are very accurate but the MPH's are off by as much as 5 mph. The one thing you have to remember is that the gtech is very dependent on the topography at the line. In other words, the gtech compensates for inclines by you tilting the unit to zero out, but that is only true at the start line. If the incline changes midrun, your times will not be accurate. At the track where it's dead on level road, the times are within the advertised accuracy totally. I have noticed though that it is very much off when you have changing road conditions. Go to the track and compare. Your car may be near/at those times anyway, but real accuracy will be at the track.

 

If you read the g-tech manual, it states that it will show a higher trap speed because it gives you the speed you are traveling at the end of the 1/4mile, when you are at the track your trap speed is actually what you average through the last 60ft..