e32 is another great choice! Big fan myself. There are other members on this board that could help you more, but I know the rads in those things were notorious for cracking, and there were a few recalls I believe. Also, the rear lights were bad for corrosion so sometimes making a burnt out light work is as simple as cleaning the connectors.
Other than that, I'd have to do some research for common e32 issues. But, it's a 18 almost 19 year old car. Anything could be wrong with it, I'd be willing to bet that there would be the odd electrical issue, like heated seats not working, nothing major, but you'd have to decide what you can and can't live with. Just check it over as closely as you can paying attention to rust and fluid leaks. Just my advice.