When I removed my wheel spindles on my new S thou, they already had a coating of factory lubricant on them. This was a sort of silver or aluminium colour. I have copper slip in my garage which I use on fastenings mainly. I also have a tin of an aluminium assembly grease, not unlike the stuff applied to my spindles by BMW. This was given to me by someone who's son worked as a mechanic on helicopters in the RAF, and I use this from time to time, depending on the job. I cleaned off all the assembly grease that BMW applied and coated mine with good old HMP wheel bearing grease.