[TB///M3]

I'm just bored waiting for my M235 to go into productions, so to pass time, I research things..

So I first went to Mobil's site and input the M235 and they recommended
Mobil 1 - 0W-40 then I went to Castrol's site since bmw recommends it.

Castol recommends 5W-30.

I read the manual you can go 0/5w - 30/40 range.
My opinion both is not that big of a difference, but which would you choose?

Also, manual didn't say how many quarts the N55 motor takes.
Anyone know for sure?