Wanted a dead pedal -- and was bummed by both offerings in the '04 and '05. Could tell the Holden unit wasn't going to work -- because the driver's side kick panel has nothing to mount on (just a plastic cover with electrical housings in back of it).
Found a photo of a GTO with the carpet removed. Turns out the firewall in front of the panels is perfectly angled to mount a dead pedal with a simple L bracket. Created a cardboard template. My Dad saw it, rummaged around in his shop -- and, of all things, had a piece of metal identical in size. Painted it black, mounted the pedal to the bracket with an aircraft screw, cut a slit in the carpet, drilled a couple of holes, hit 'em with some self tapping screws, filed the screw ends down (as they appear in the wheelwell), and hit the screw ends with some asphalt paint (the identical stuff used in the factory).
What's cool is that the factory mat can be positioned around the plate -- so, again, the whole thing looks like it came from Holden. The carpet looks a little wonky here -- but that's before I put a Velcro pad in place. The carpet and dead pedal aren't going anywhere. It makes driving the car a heck of a lot more fun. While the pedal looks a little off center in the image above, it's just a result of the angle of the shot...