BMW Repair: BMW Rear end, uneven tire wear, strange angle

Question
A pal wants me to sell a car for him which he says has a problem with the rear diff. This is a 1993 325i model with around 174k on the clock. The rear wheels are at a strange angle, being further apart at the bottom than the top. There is also a pretty awful grinding noise coming from the rear, moreso in reverse I'd say. I havnt attempted to crawl underneath the car as yet as Im not so much into becoming very oily these days unless I'm doing my own car. I am almost tempted to take the guys word for it that the rear diff has popped somehow, but, I have to provide the buyer of the car with facts, and I would like to know what the problem is myself, I'm like that!

I would greatly appreciate any words of wisodm you can find the time to provide.#

Best wishes  

Answer
Phil,
 The rear tires should be tilted in slightly more at the top than the bottom (if you are standing behind the car and looking down the side of the car).  This is called Camber, it allows the car to corner better.  Lowered vehicles have exagerated camber and will cause uneven tire wear and other problems.  

 The grinding noise could be a number of things, and I really cant put my finger on any of them with certainty.

 Good luck,
 Josh