Might be , but when I put the Sachs kit in my last 535, I suddenly heard this awful rattle coming from the front. Turned out to be the fog lights. The "ball" broke and they were sort of "floating" around and making all kinds of noise. Fixed the fog light mounts by drilling a hole in the ball and reattaching it to the housing with the screw and epoxy. No more noise.
So the moral of the story is look around, it could be something unusual like that.
Mike Holbrook
Meridian, Idaho
1992 535im, 17", Euro M5 Throwing Stars 8's & 9's, FK-451 235/45s & 255/40s, M5 Sway Bars 25/20, Conforti chip, Lowes Ram Air, glass sunroof