After owning my '92 BMW 535 for a couple of weeks now I've noticed a few issues. First, there's a vibration in the steering wheel under soft to moderate braking between 40 - 70 mph. It isn't noticeable if I brake hard or outside the speed interval mentioned. The car also has a very nervous behavior, to the extent it's difficult to stay in the same lane, at high speeds (120 mph and above). I've checked the tires and tire pressure and they're fine. Another problem is that the windshield wiper on the driver's side is unable to clear the water off of the windshield at freeway speeds. It's like it's floating above the windshield, which is strange since it works perfectly at lower speeds. The traction control is beginning to drive me nuts too. If I'm accelerating and hit even the smallest bump it cuts the engine power with a big jerk, and don't get me started on driving over speed humps.
On the positive side, the rough idle is beginning to clear up. Lots of hard accelerations and high speed driving after pouring a bottle injector cleaner in the tank seem to do the trick.
All-in-all, I still think I made a good buy. My dad even called it "a real car", as opposed to my previous BMW, after giving him a ride... :-)
Ulf