This is my first post to the board here. This weekend, I am going to be looking at a 1990 535i w/ 135K miles. Add service records. I am wondering what I should be looking at specifically, are there any common problems I should be aware of? I currently have a 87 325is, so I'm not totally new to BMWs, but I'm not familiar w/ the 5 series. TIA for any advice.