Front Grills
1. Pop the hood
2. Pull off (remove) the rubber strip that runs across the bottom of the engine bay (closest to the front grills)
3. Unlatch the tabs that you will see after you take off the rubber piece. It should be a total of 3 top clips. Just press them in and push them out a little so they stay depressed. Then depress the bottom clips, there are only two clips on the bottom of the grille. Push them out just a little as well. Now there is 1 clip on the left side and 1 clip left on the right side of the grille, so unlatch them. Once they are unlatched pull the grille out. If it doesn't come out, check the clips and keep trying. You will need to fit your hands in between the fins for the first grille removal. The second grille removal is much easier as you can reach across and see while removing the clips.
4. To reinstall, align the grille properly (align the clips) and then press in until they are all latched.
5. Reinstall the rubber trim piece.
Side Gills
1. Grab a hold of the side gill and push downwards from the top while slightly pulling.. you will be removing the gill at a angle.
2. Reinstall the opposite way. Insert the side gill in a way where the top makes contact then push it in (again it installs at an angle)
Here, in this image you can tell where the clips are. This photo is from RPI's Ram Air Intake Scoop DIY (Race Precision).
TOP = THREE CLIPS
L SIDE = ONE CLIP
R SIDE = ONE CLIP
BOTTOM = TWO CLIPS
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If you search, I am sure you can find more photos. This is the best I can explain it using just words and the above photo showing the clip locations. The front grills are somewhat tricky.. OEM is easy to get off compared to having to remove aftermarket. I always break aftermarket grills when removing them. Unless they are a quality OEM part, then they are rather hard to break when installing/uninstalling. The side gills are much easier to remove and install.