I jacked up the car at the diff so both wheels were in the air. I marked the drive shaft with spit and stared at the "P" on the tire. One rotation of the driveshaft gave me one half of a rotation at the wheel. So it was a 1:.5 ratio or 2:1 driveshaft:Tire rotation.
And then I found this:
Mine would be the "M5" block so it looks like the only other car with my diff is the 1.8 190E...