I have a GN FMIC and had to remove the flat piece as it was contacting the FMIC. I couldn't do the grill springs either. Once the flat piece is removed, take a look at the corner holes. They actually line up with a hole nearly directly below in the bumper support. I rat tail filed the holes out to around .25 inch and dropped in a 2.75 (maybe 3", I forget) carriage bolt. To make up the space between the underside of the grill plastic and bumper support, I used a hollow round nylon spacer. I was able to snake my arm under and up to drop the bolts in from the top, and used my other hand to line up the spacer holes.
Unlike the original style, my grill now has no flex in it (no springs) and remains solid.
Spacer below: