well lets get started Remember this is for 84 - 87 Fiero model years. The 88 already has just front hubs without attatched rotors so some of this thread post process is not performed.
I am going to start on the fronts first so....
Break torque on the front wheel lug nuts on both tires then lift and support car. If you have the ability to lift and support the whole car then go ahead it will save a little time later. Remove the front wheel and set aside. Take off the factory brake caliper remove the hub/rotor assembly DO NOT loosen the brake lines from the caliper, just hang it out of the way. You will find it very easy to bleed the brakes later.
Take off the rotor/hub assembly, then the caliper bracket from the front spindle you no longer need this bracket but save the bolts you will reuse them with a new lock washer.
take the dust shield off and go modify it.
with the help of my little buddy and 10 minutes I cut the brim off the shield and the part that does not have a wall on it it needs to be trimmed back a bit to clear the adapter bracket, if not then they will have a conflict of space which will do 1 of 2 things. 1. it will prevent the dust shield from going on if the bracket is in place or 2. if the dust shield goes on first it will cause the adapter bracket to at an improper angle alignment to the rotor. This is the only modifications needed to fit but if you are like me you will trim and cleaned it up a bit more.
Now the fun the rotor/hub. Find a piece of 2X8 about a foot long, set the hub assy lug nuts ends down on the board and find any ole piece of wood then it place on top of the hub. using a good heavy hammer give it a nice smack. This should leave lug indention marks on the 2X8. Drill them out you will use this later to install the new longer lug studs. Remove the lug studs yourself or have the machine shop you are going to take the rotor/hub to do it, your choice. You can easily do it yourself by taking the Mini Thor and drive them back out. Be sure to place the hub assy inner side down on another piece of would so you do not damage the inner seal surface. Now have any local machine shop remove the rotor portion of the rotor/hub assembly. Mine cost $70 for both. Once that is done, drive in the new longer lug studs, align the hub over the 2X8 that you drilled the holes through and beat in the studs. You are doing this for 2 reasons; 1. as you put more studs in you run out of hub lip, 2. as more studs go in it jumps around a lot less because they are in the holes of the wood which allows a much greater drive force from each hit. Do this till all the studs are in 1 hub and 1 HUB ONLY. You need the other to remain studless as a guide for drilling the new rotors
ATTENTION if you are going to use an aftermarket replacement rotor/hub assy pay attention to the lug stud holes, they may be a larger diameter at the press in point but still use the factory M12-1.5 pitch. If this is your situation then you will need these lug studs Dorman 610-427.
Also with these you will need to taper out the backside of the new rotors a little because part of the grip portion protrudes past the mating surface of the rotor to hub
These last 2 photos are not mine they came from a thread posted by Fieroguru on PFF. I claim no ownership of them. I am using them for reference only