Its not much of a "bracket"... All i did was take 3" stanley mending plates (just flat plates) and for the side of the speaker towards the rear of the car, i just brought them together and used the existing screw on the part in the center of the opening. On the front, i attached them to the speaker, and then with a pencil marked where the holes needed to be for it to line up with the holes that are there. On the top one there is a piece of metal inside that has a hole i used. The bottom i used the holes on the plastic. Then i used little rubber spacers to make it so the speaker was even space from the panel. You can IM me on aim, icq, yahoo, or msn if you want. My sn's are in my profile. Just lemme know if u have anymore questions...
And yeah the holes was easy, i just marked it, then drilled a hole with the biggest bit i had, then used a mini-hacksaw to cut it out, then smoothed the edges with my dremel tool.
btw... those are 4" grills... all that will fit on that panel