Here are the few things about the E39, and other M62 V8's:
Anything over 180K is a ticking time bomb if chain/guides are not done.
Rear springs tend to go every few years, car is too heavy for them.
Cluster and radio pixels will die sooner or later, if not already.
Cupholders will get broken.
Door handels will get broken, both inside and outside.
Rear window regulators will go.
Power steering leaks.
Oil filter housing mounting "rubbers" will give.
Wood trims will crack, if not already...
With the bad stuff out of the way, I must say they are great cars, if you DIY most of the things you will save BIG $$$, and it only takes some time and basic tools...