Originally Posted by dcg71
Looking at the m5 /335i comparison pic, there's a huge difference in the shape around the grill and light area between the two. You'll be throwing away the top 1/3 of the bumper and doing some heavy customisation I imagine.
Ideally you would just chop the bottom of the M5 bumper and mate it to the F30 bumper's top to get the OEM fit with the M5 aggressiveness. Easier said than done, obviously.