Hi, I have a 6 year old 360R with and LSD (BMW I think) and at a recent service was informed that the diff oil was black which indicated the wear in the carbon plates and it should be refurbished - not cheap. The car has only done 8,000 miles and a few track days so it seems strange to me that the LSD should be failing so soon. Any advice whether this is normal and should be done or is maybe over cautious and a bit of up-sell from Caterham South?