Stay away from early model 530's. The nicasil block is prone to cracking and other premature engine wear. They did recall the car soon after the problem was noticed and replaced the engines under waranty up to 100,000mi. or something. But in my opinion it is best to stay away from something like that all together unless you can know for sure the engine was replaced.
Every 530i I see is in pretty rough shape. But at the same time, just about every other e34 I see is in pretty good condition.