^wow that's impressive, i thought that grille was just a direct swap in/out!
To the OP, i went through this recently by having to take my grilles out for a different reason.
Regarding just that, it is a total pain in the ass!! The bumper itself is cake to get off, after that you can proceed to remove all torq screws inside the bumper. From there you work from the outside in removing the fog lights, then fog light grilles. as you do this, you should find that the fog grilles, lower grille surround and lower grille all come out 'as one unit' which you then can dissect on the floor with the bumper out of the way.
So work from the outside to the inside, but the other tip is to take some various flathead screwdrivers to gently pry at all the tabs before getting into it, to get them somewhat ready to unfasten themselves, otherwise every time you work one clip off, the next one might clip back in. The use of screwdrivers was crucial, in my opinion. Luckily, no tabs actually broke on me, as they are all quite flexible, and I had no issues getting everything to snap back into place afterward, with no signs of misfitting or damage from the outside.
Have fun and do it on a carpet to avoid damaging the bumper's paint. Be patient and methodical, as it is REALLY stubborn to get apart, but the end result for you should be worth it.