OP - since you live in NA what ever oil you use it should have a:
"BMW Long Life-1 (LL1) rating" on the back of the bottle. There are not many oils that have this rating! Make sure it says:
LL-1.
I believe your owners manual will say to use these viscosities:
0W30, 0W40, 5W30, 5W40
Here is a very good writeup on how to change your oil youself, if you are so inclinded. But most dealers charge around $120 or less. Still I prefer to change my oil myself. Even though this DIY is for a 128i, it is all basically the same. You can read thru it where I posted my DIY oil change for my 135i and the tools I used.
http://www.1addicts.com/forums/showthread.php?t=301440
And here is a good thread on which oil to use...
http://www.1addicts.com/forums/showt...+long+life+oil
Dackel
You should also change the filter when changing the oil.