[realworld51]

Except to say the oil is priced as if it were liquid gold over here in UK.
£13-15 per litre ($21) - and only available to buy from the BMW dealer on exclusive deal with Castrol. So 4.5 litres will set you back a fair bit.

At the risk of starting a 'what oil' discussion - do BMW allow any other types without voiding warranty? The RT at least allowed you to use cheaper Actevo.

The only requirement would be that whatever you use meets the stated rating specification. And any high-quality full-synthetic lubricant will be more expensive than dino oil.

This isn't an item where I would cheap out.