Re: BA XR8 - Effectiveness of LSD (Diff)
There has been other threads about this previously and I think the conclusion was that the diffs in the new XR8's were not actually "LSD's" and are even labelled differently on the casing. Either way the breakaway point in BA's is lower than in older LSD's (i.e it is more prone to single-wheeling).
Try doing a search on the topic, there were some other very dissapointed customers; and so there should be, the diff in my EF after 8 years of poor treatment is only recently starting to show signs of not being an LSD.
Cars with LSD handle and perform differently to cars without LSD, I would hate to think that someone in a BA may have to take evasive action on the road in a $50k+ car and have the LSD (or whatever its called) behave differently and cause an accident.
Go to Ford, and if they give you the run-around, go to a diff place, get some advice and see if they can run it through some tests.
Good luck and let us all know how you get on.