I am one of the guys that almost had to visit a mental hospital when trying to exchange the grilles.
I got so darn pi**ed off, because my thinking was that something so easy - could not be that hard.
But, OK - even I managed after my third try...
And then - I saw it as quite easy too. Huh.
I have let out a lot of frustration in this thread:
http://f15.bimmerpost.com/forums/sho...hlight=grilles
My way was to REMOVE THE GRILLE FRAME/RING SEPARATELY FIRST.
That is the hard thing.
The later step to actually snap out the rib-unit is very obvious and easy because you can then see the clips for that unit
To put in the new grilles are equally simple, and then the whole unit/grille can be complete. Push it straight inn, and you hear snap-snap and you're done.
You will need a thin tool, like long screwdriver, lets say no more than ca 1,5mm in diameter.
Lay your new grilles down and look at the actual locations of the clips (so you can see between which ribs they are located).
The 3 last clips on the underside need just a little press from the tool to come loose. No dangerous "plastic cracking" sound should be necessary.
Pull gently with your free hand from the outside.
You may also try to split the new ones you have first - as a test on how to do it.
Best
Bent