In Reply to: E39 M5 rear spoiler mounting question posted by TSB on December 12, 1999 at 21:08:17:
I ordered mine from Bekkers. The genuine E39 M5 rear spoiler costs about $200 whereas the dealer here charges about double.
The genuine M5 spoiler comes with double sided tape which glues really tightly. It does not require screws. The bodyshop people told me that the spoiler is too small to be screwed on.
It seems to be an easy job to put on the spoiler, but I had the bodyshop done it for me for perfect alignment.