I am not sure what my rear gear is but 2000 RPM= 80 MPH 1600 RPM=65 MPH. I can assume I have 2.73's.

Possible rear options for an A4 car are 3.23 or 2.73. That is a ratio variation of 1.18315.

That means 80 MPH becomes 67.6 Miles per hour at 2000 RPMs.

So

2.73 gear = 2000 RPM at 80 MPH
3.23 gear = 2000 RPM at 67.6 MPH (2000/67.6=29.856)

Now you have the total ratio you can plug in any MPH. 60 MPH * 29.856 = 1791 RPMs

Of course all of that is base on the accuracy of my tack and the unverified fact I have 2.73's and my eye sight going down the highway looking at gages