[Ajc1100]

After over a month of searching and seeing a few different e90s, I've finally found the perfect one, a 2009 black e90 with 53k miles. The car is in near perfect condition with no scratching or swirling on the paint, the only defect I could find on the car is a small scuff on one of the rims.
I do have some questions though. When I cold start the car, if outside or with the windows down, I can hear a noise that sounds exactly like an exhaust leak from the manifold, but after a few minutes it disappears once the car warms up. I hear this is normal, something to do with the cats heating up, but wanted to make sure. My 2nd issue is that I get some squeaking inside the car whenever going over tall speed humps, or pulling up slope like a driveway. To my knowledge it's infamous on the 4 doors and is simply the door seals squeaking. Is there a solution to this? I've heard of people taking it to a bmw dealership to get the seals treated. It's not a huge problem to me, just a bit of an annoyance.
I also plan on changing out the bearings in the next few thousand miles once it's time for an oil change for some peace of mind. If anyone can recommend any good shops that can do this in the San Diego area please do so! Any other preventative maitenance you guys can think of would be appreciated! Thank you.