3 series maint/oil changes

I've just ordered a new 3 convertible. This will be our 2nd 3, the first being a sedan. The computer monitors oil quality / life, and tells you when a change is needed. On the sedan it went nearly 20k miles before saying it needed a change. I was not comfortable with this, but I'm kind of a simple guy. I usually change the oil myself more frequently during the break in period and then start normal intervals. Nothing about maint. seems simple with these cars.
I'm thinking that on the new car I'd like to start differently. I'd like to ask you folks who've been there done this for advice. I'd like to change the oil myself at closer intervals. I know the filter is different, like up top and just an element in a housing, and I think there's some type of rubber thing or grommet? What is there, and is the dealer the best source or somewhere else like a web site? I've researched oil and would like your thoughts on this as well. Is BMW oil best or mobil 1 or AMS oil for the vehicle? (certainly I know some of this is subjective) Did I read 0/30 was the best choice? (I live in Maine - so this will be a warm weather only driven car)
How about the computer? Once I change oil, will it sense that the oil quality is acceptable, or does it need to be reset somehow? Oh, and don't get me started on the no dipstick thing!!!

Thanks - I know this is lengthy - I'm a rookie at this...

have you checked out www.bobistheoilguy.com ?

bob the oil guy

had never heard of it, very informative - thanks!

Just out of curiosity, do you guys always replace the oil pan nut and washer with every oil change?

az3579

I alwaysinspect it, and then usually reuseit, assuming the washer and the threads of the plug are intact.

The general consensus is that 7,500 mile oil changes are much prefered; especially on the 335, because of the relatively high operating temps the turbos produce.

Spend some time on www.bimmerfest.com . There's no shortage of discussion of this issue there and almost every question you could ever think of you can find an answer to there.

I have read that 3-5k is more prudent with the direct injection. some guys say at 1000 miles the N54 has wrecked the oil....

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1200595&fpart=4

a lot of those guys do oil analysis BTW