Jcma,
Did you buy a new 530i or an older one? If you bought a new one, I don't really know what to tell other than what I've suspected has been going at BMW over the last couple of years, which is that build quality has gone down. If it's an older one, it might be that person just drove it too hard (like a lot careless drivers) and the car took a beating and now its catching up.
Additionally, where is IL do you normally drive? Are you from around Chicagoland? If so, those roads (potholes) can be brutal on cars. I bought my 3er a year old from a guy in Barrington who pampered it; it didn't squeek or rattle a bit, even over some of the rougher roads like on the Edens and Bishop Ford. But now as I'm nearing 80K (76 to be exact), I think the shitty Chicago roads are catching up to it and am noticing more subtle rattles and creaks in the dash and in the rear over rough roads...but it's still pretty solid for the most part.
Similarly, a good friend of mine has a 2001 X5 that he bought brand new and is experiencing similar problems, though with much greater intensity than in my car. I know he's a little pissed, especially after hopping back and forth between his X5 and his dad's 2000 LX470, which is near silent. My sister's 93 Camry with 130K is also pretty quiet.
Another thing that sucks is that IDOT oversalts the roads and after every winter there are a shitload of deep potholes (or more like pot streaks/lanes in some cases) in the area. But it seems to me that Japanese cars are a little more resitant to rattling/squeeking that German/American cars.
Just my 2 cents...