It is used for lubrication.
It is a combination of synthetic oil and conventional oil.
No, you can even mix synthetic with conventional oil. It will do no harm at all.
Yes
That's okay.
5w-20 of any synthetic motor oil brand.
The Correct Motor Oil for this vehicle is a 10W40 Synthetic Motor Oil
Synthetic motor oil.
Yes but once you do there is no turning back and no mixing regular motor oil ever again with the synthetic oil....only straight synthetic....or use semi synthetic....now that can be mixed with regular motor oil in a pinch.
SAE 10w30 full synthetic.
It's a performance motor so full synthetic oil, castrol is recommended but mobile 1 can also be used as well as any FULL synthetic oil.
depends on what oil your talking about if your changing the motor oil is synthetic oil that must be used. BMW recommends castros synthetic oil but its all your choice on what synthetic oil you want to put in it. i have royal purple in my 325i 2003 and it feels alot better to drive.
Yes, anything mid 80's and up can be switched between conventional oil and synthetic oil. Anything older (that was around when zinc was found in oil, or when cork gaskets were used) should stick to conventional oil. It's actually federally mandated that conventional and synthetic oils be interchangable.