http://www.realoem.com/bmw/showparts...67&hg=41&fg=60
Is part number 4 in the picture the one you're talking about? Two bolts hold the frame to the car and four screws hold the plate to the frame. I think the hole locations in the plates themselves are standardized. If you do in fact have part #4, I'm not sure where the problem lies.
As far as the front is concerned, on my sedan, the plate holder snaps into place where the black trim is located on the bumper. The plate then screws into the holder. For the coupes, I think there is a similar holder, but I don't know how it is actually attached to the bumper (see link below). IIRC, coupes were never delivered with the holder. I believe dealers actually drilled holes in the front bumper in order to directly attach the plates.
http://www.realoem.com/bmw/showparts...79&hg=51&fg=15
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