I have a 2011 gmc sierra pickup. I want to mount 2 m4's in the grill ..They don't fit in the grill slots but they aren't big enough to cover the "ribs" of the grill..Any suggestion ??
You could sandwich the grille between two cleanly cut black plastic panels, slightly larger than the M4. If you use black rubber washers between the plastic pieces it will stop it from sliding around.
Here are the M4's in my 2009 Sierra's grille. the light head fits perfectly between the grill slots (although it looks a little blocked in the pic because of the camera angle). I used some flat stock aluminum, painted it flat black, and mounted them to the radiator supports behind the grille. They're pretty covert when off, and OMG bright when on. Oh, and they're Red/White.