New E46 owner...refugee from Porsche

Hi, just saying hello and introducing myself. I just bought a black on black 2002 330ci with 79 k on it, moving on from a 1976 Porsche 911s that I restored/made track ready over a period of a year. As a college student, as much as I enjoyed the pureness of no power steering or brakes and an engine in the back, it was too impractical. So here I find myself, with what my resources could manage, the next best thing. However, the 330 makes up for what it doesn't have with comfort and compromise, something that was never considered while building the 911.
I am in a new land now, essentially starting from scratch when it comes to knowledge about this BMW. As I said before, I did all the work myself on the 911 and work/drive for karting teams, so I can handle most projects.
I have been lurking here for about a week, and have read a lot if different opinions on things. So, from the get-go, what are the things I should keep a watchful eye over in this car, what maintenance should I do right away? What is the best oil/filter for my particular engine, bar none?
I plan to install sport bilstien's and h@r springs in the near future to lower it while keeping a smooth ride, and my wallet not completely empty. Seems there isn't much to do with these engines unfortunately without a bucket of money equal to what the car is worth. I guess I won't spend much time there.
Anyway, thanks in advance, as I soon hope to help somebody from the knowledge you all share here.

Hello.
The cooling system seems to be the weakest link. Look for Mango's thread.
OEM oil filter and I'm running Mobil-1 0w40 because I get it for free.
It's a great car and relatively easy to maintain.
Also check rear sub-frame mounting points before dropping any real cash.
Enjoy!

Ok I will read up on that. What is the correct way to check the condition of the subframe/diff bushings?

Originally Posted by Pole position

Ok I will read up on that. What is the correct way to check the condition of the subframe/diff bushings?

not to worry. Your 2003 and low mileage doesn't have these problems yet.

Subframe is mostly on 1999-2000 e46s

and diff bushings don't become a problem until maybe 150k-200k.

Just dont act like a Tokyo drift king with ur car

Do a search on this site for sub-frame.
If you have questions, it's very likely they have already been covered here.