There are different options on the audio system, the basic one is pretty poor but can be upgraded, then there the hifi and then the top hifi, you can tell the better options if it has 2 large circular speaker grills behind the seats, there’s a good description in the link below
https://z4-forum.com/forum/viewtopic.php?p=1735432&hilit=Top+hifi#p1735432
Also make sure it has Bluetooth connectivity for the phone and music as these were separate options.
Auto lights / wipers are nice as well, although you can just leave the lights turned on with the switch and they turn on/off when you put the ignition on/off.