Well, here we go, round two for removing those center grills found on the 06-07 Impreza's.
What you will need to complete the job without damaging the grills or the paint on the bumper cover is one small common screwdriver, like the one pictured here;
Start out by removing all the quick release plastic clips found across the top of the bumper between the two headlights,
Next, you have to remove the center grill section. Here you will see the two "clips" on each side of that grill that you need to pull towards the center of the car to unfasten the center grill.
To do this, put one hand behind the bumper cover, pull each of the two tabs toward the center of the car, on each side of the center grill asembly, while pulling lightly straight outwards with your free hand.
repeat for other side of center grill
Now, you move on to each side grill asembly.
On each grill, there is a total of 4 "clips" that you need to disengage to release the grill asembly. If you use my method to release these clips, you shouldn't damage any part of your bumper cover or the grill assembly while removing it.
First, start with the "Tab" closest to the opening for the center grill asembly, pictured here;
To release the tab, push it outwards (towards the headlight) with one hand and the other hand applying light outwards pressure on the grill, just enough to pop it free from the bumper cover, then move on to the next tab.
Now, the second tab which is located on the lower center edge of the grill asembly, pictured here;
To release the tab, push it upwards (towards the hood), again while applying light outwards pressure on the grill asembly.
Next, you'll work on the last two tabs, which are located on the outboard edge of the grill asembly, between the grill and the headlight. Pictured here;
Start with the top tab, apply some outwards pressure on the grill asembly so you can barely see the two tabs, like so;
insert the screwdriver to pry the top tab outwards (towards the headlight) on the bumper cover to release the top clip.
Once the top clip is released, you can move on to the lower clip, repeat the same procedure with the lower clip.
Next, pull straight out on the side grill asembly, if you encounter very much resistance, chances are one of the other tabs have reengaged with the bumper cover, so recheck all 4 tabs, then pull again.
Well, hopefully this helps some of you members out there, when your installing those fancy Hella horns, or clearing your headlight, or heck, even changing a bulb in your headlight asembly.