To my knowledge, the CRV differential was used because the trans was CRV. Since the originoal concept was AWD, it was nescessary to keep the final drive ratios the same as to not stress the drive line components any more than they allready are.

Now that the car is RWD, pretty much any Diff could most likely be used but the CRV unit is already in there and seems to be holding up fine...

-MR