Common style 5's: 17" version found on E39 cars with the sport package. The E39 has a larger hub; a hubcentric ring is needed to make it fit correctly. Read bmwe34.net or do a search for more details....we discuss it all the time
Not so common style 5's: 17" version found on some late E34 540/6 cars; has the correct hub size. 18" version found on some early E38 740i "sport" cars; again, has the correct hub but probably a 23mm offset.
Buy what you like. Ultimately, #1 (you) is the only person who'll care about them and the only person who'll clean them. Style 5's are a pain to clean
best, whit