e60benz

Does anyone know how accurate G-Tech timers are? I know what they claim, but has anyone used one at a track and compared 1/4 mile or 0-60? I got one and recorded 4, 0-60 mph and 1/4 mile runs (back and forth on the same stretch twice).
0-60 average 4.55 sec.
1/4 13.35 @ 113.2 mph