Ok I figured it out after talking to the cervini's guy, I also made my own little set of directions if anyone wanted to see as well.
Cobra Rear Bumper Cover Install On Fox Body Mustang GT
Removal
1. Remove plastic push-pin retainers from bumper support/gt bumper cover (I used a large pry-bar) there are 3 of them per support.
2. On the inside of the hatchback remove the interior plastic trim along the back where the lights are, and along the sides of the hatchback up to the area where the hatch support lift struts are. (just need to remove enough screws to move the plastic out of the way)
3. Along the back of the hatchback the bumper cover is held on with a stud plate with nuts on the inside, remove these nuts (they have black sealant on them to prevent leaking but aren’t on very tight.
4. On the sides where you removed the trim there are nuts holding the gt fender extensions to the fender (3 of them per side). You might need to pull your trim back and out of the way to gain access to them.
5. Here comes the hard part on both sides there are extension brackets that hold the rear/sides to the car and they are buried down the bottom of the side panels, especially the passenger side is hard because the gas fill is in the way, I needed to disconnect the plastic gas fill shield from the fender and slide it out of the way to get access to the bottom bolts on the cover.
6. Once all the bolts are removed the bumper will slide right off. You’ll want to remove the large stud insert from the old bumper cover as it needs to be put back into the new cover.
7. At this point you want to go under the car and remove the gt bumper cover supports either by drilling the rivets out or by brute force (this is what I did with the pry-bar) as getting a drill in there doesn’t seem easily done.
Installation
1. Once the bumper has been painted it can be installed, all you need to do is transfer the stud bracket to the new bumper, slide the bumper on and tighten nuts with some weather sealant.
2. You’ll notice the new bumper has an extra hole on each end, I was told by Cervinis that you don’t need to use it, but I opted to install my own small push-pins for added stability.
3. Once the main bracket is on, you can go under the car and install the provided bumper brackets to the tank straps.
4. The old gt’s fender extension brackets aren’t used on the new cobra bumper, instead they are held in place with double sided 3mm auto body tape.
5. Lastly the fender screws are tightened on each side and you’re done with the bumper, replace all your interior plastic trim and check for straightness of your lines.
