I want to change the oil in the rear diff of my MY99, what do people recommend as a good oil. I assume the two plugs on the back of the diff are the drain plug and the fill/level plug ?

Most people on here use Castrol Syntrax I think. Seems to be highly recommended.

Gavin :)

don't forget to check that your car hasn't got an LSD (depends on model) if so you will need proper LS oil such as castrol LS..

You are correct about the drain/refil plugs

Just for info (thanks to the people who mentioned it recently, as it almost caught me out), the two plugs can be a pig to undo, but will shift eventually.