[steely]

No problem - the car just won't start. BG reads the flywheel pin, DG reads the teeth. I forget the german, but BG is the reference used only for starting and DG is for speed. The ECU won't allow a spark if they are flipped. Each develop the same type of signal, just the rate is different, and the ECU/DME ignores them if wrong. When I replaced mine last year, I marked them, but still managed to flip them. The mating plug-side labels had come off. Yeah, I had a 50/50 chance and messed up, but after a few minutes troubleshooting, I switched them at the plugs and she fired right up.

Auf Deutsch:
PS..in German...
BG = Bezugsmarken geber ( reference mark identifier or "giver")
DG= Drehzahl geber ( revolutions identifier or "giver")

translation credit to Wil Ferch