Just a follow up to my previous post; I had the alternator replaced under warranty and I could tell the difference when the car was at idle and reving the engine that the alternator whine was gone. Great, thanks BMW!
The only problem now is that I still have the whine/rumble when I drive the car, just up to 70km then it gets absorbed by the other road noises and is un-noticable at highway speeds.
The SA said it's normal for the 328i's with automatic transmission and that seems to be supported by posts on other forums but I just can't imagine BMW making a car in 2009 that sounds like an old truck going through the gears, love the car but this drive whine/rumble is really anoying and I can't help but wonder if it's a harbinger of problems to come.
Has any one else had this experiance with their 328i and what solutions if any have been talked about?