Hey Bimmer guys v.E34

Yes, they are pretty much just as reliable. The 525 uses the same motor as the 325 does. The 535 is a pretty stout engine as well. I kind of recall some issues with the early 540 motors due to the nickasil flaking off the cylinders, but I would research that a little more to confirm.

http://bimmer.roadfly.com/bmw/forums/e34/