For my BMW M6 with the S85 V10, I was previously using the Castrol Edge 10w60 Supercar oil which I believe is what the engine came filled with from the factory. The Castrol oil is one of only two 10w60's that are readily avaliable from local shops where I live, the other being a local Australian brand (Penrite).
However, my mechanic's supplier started importing Ravenol a while ago, including their RSS 10w60.
I decided to give it a try, as it looks very good on paper and has some friction modifiers that the Castrol lacks, so potentially a little better for preventing wear. The flip side is it's a lot more expensive, easily twice the price of the Castrol oil, if not more.
Obviously I want the best for my engine, but do you think it's worth paying extra for the Ravenol, or any differences to the Castrol will be negligible and I should save my money?
Data sheet for the Castrol Edge 10w60
here
Ravenol RSS 10w60 data sheet
here