Was reading some info on the ISTA+ regarding recommended fluids for the differentials. I know different DIY'ers have used different kinds. But I was curious about any drawbacks to using cheaper alternatives over the more expensive fluids recommended by BMW (for e70 N55 motor, per ISTA+ updated 2016) before I tackle this DIY:

1. Front differential: Hypoid Axle Oil G2 (BMW part no. 83-22-2-413-511)

2. Rear differential: Final-Drive Gear Oil Saf-Xo 832514 (BMW part no. 33-11-7-695-240)

3. Transfer case: Transfer Case Fluid - DTF 1 (SAE 75W GL-4) (BMW part no. 83-22-2-409-710)