This diff' was bought brand new from a BMW dealer at a cost of almost £1000. It has been run for less than 100 miles in the LMP. The ratio is 3.15, which was found to be too high for track use.

It's on Ebay, with pic's:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=10374&item=2486823774&rd=1