Just a heads up to anyone removing/replacing the kidney grills. This writeup was great first of all! But there is one thing I encountered which anyone should look out for, that is, when pulling the kidney grill out, if you pull the bottom half out first at a bit of an angle, you risk scraping paint off the top left and right corners of the bumper where the top of the kidney grill is, since the edges of the kidney grill tend to gouge it out... see pic below...
Luckily I had touch up paint and you can't tell what happened unless you knew where to look.... but to avoid this just try not to pull the bottom half out too much before starting to remove the top half.i.e. don't create too much of an angle when removing the kidney grill. try to pull out as straight as possible.