[Bill Baer]

I use RPM Performance system designed for .90 class racing.
I. Look at (in order of importance)

Driveshaft RPM, motor RPM, throttle position, fuel pressure, voltage, motor temp, trans temp.

I haven't found a use for the G-meter it usually get's disabled when the driver kicks the cable entering or exiting the cockpit.
The throttle position sensor has been temperamental and usually needs to be re-calibrated before each use.
We usually focus on the driveshaft RPM to try to determine if and where the car spins the tires and compare it to the others for that track .