I will totally agree that it made a difference in my driveline noise. Especially noticeable when deaccelerating or coasting. My rear diff sounded terrible before, not I barely hear it.
The weird thing I noticed was that the oil looked different from the front and rear diff. I would have assumed that they put the same oil in at both ends? I guess even if the dealer I purchased it from happen to put the wrong oil in one of them, I only have about 180 miles on my P520. Couldn't have done much damage in that amount of time. I was just happy there was actually oil in it... they left so many bolts loose and missing when I bought it.
Rob