Using the mfr's diameter in
Liquid's calculator, the gray 19-tooth gear in the car should be correct, but the speedo showed ~9% high. Using the tire's rolling diameter of 25.79" (back-calculated from the RevsPerMile), it recommends the orange gear. But even after installing the orange gear, it's still ~4% high at highway speeds. Below 55, it's dead-on.
The drive gear in the transmission tailhousing has 8 teeth.