[1. Remove the grille first. Two screws on the outer corners and towards the middle you will see two black plastic clips (they are smooth). Use a slotted screwdriver to pull these out and then pull the clips out. Next pull up and away from you...and don't be scared to pull hard.]
I just tried that procedure on my 02 P5 and it doesn't work because there are two plastic fasteners attaching the grille to the radiator support, they near the end of the grille. The hole in the grille. These are not the two piece fasteners like the ones near the center. The holes are slotted so maybe the grille can be pulled off the fasteners after the bumper is removed.
I have a factory workshop manual and it doesn't mention removing the grille for bumper removal. Bumper removal is on page 09-10-5. Radiator grille removal removal is on page 09-16-2
1. Remove the front bumper.
2. Pull the radiator grille forward to disengage clips A and tabs B from the front.
3. Install in the reverse order of removal.
Step 2 is vague to me, the bumper is supposed to be off,
neither procedure tells you to remove the grille fasteners.
I don't need to remove my bumper or grille at present, I just tried the grille because it sounded so easy. I had to change a fog light about two years ago and did it with the bumper in place.
I have a photo but I don't know how to post photos on this forum.
Clifton