I'm doing the same thing now, although I will probably break down and buy the rear lowering springs rather than cut them because of the way they are made and I don't want to mess with the spring rate in the rear (the fronts are safer to alter). I understand that one coil will result in a little more than one inch drop, nearly 1.5 inches.
This has turned into a more involved project than I intended. I have removed the lower a-arms and discovered one tie rod is bent and the rubber bushings are wasted. A lot of PFF folks have reported that the lower ball joint can fail catastrophicaly (snap) and since I got my car used and abused I'll be replacing those now too. So here's what I've done:
Back the Fiero onto a pair of steel ramps.
Loosen but do not remove front wheel bolts.
Jack the front end up and support the front of the car with at least two jackstands.
Remove the wheels.
Hose all the bolts you can get at on the a-arms, shocks, brakes even stuff you don't think you're going to remove with PB Blaster.
Have a snack, come back and soak them again.
Remove the brake calipers (I'm replacing mine as well as the hoses) pull the rotors off (new ones going on mine as well) and remember how the bearings go on.
Remove the end links for the sway bar. I removed mine because it made it easy to get at the other suspension peices, and I was replacing the rubber bushings with polyurethane.
This part is repeated on one the the other side of the car...
remove the nuts holding the lower A-arm in place but do not pull the bolts out (yet)
Loosen but do not remove the tie rod castle bolts. Use a tie rod removal tool or ball joint removal tool to get the tie rod off the spindle.
Place a hydraulic jack under the A-arm and put enough pressure on it to raise the suspension a little. Position the jack straight out from the side of the Fiero.
Remove the shock absorber.
Loosen but do not remove the castle bolt from the ball joint. Using a Ball joint removal tool (Either you bought one, borrowed one, or got one on loan from an auto parts store) 'pop' the joint loose, then remove the castle nut(s). Now you can remove the tie rod.
Now stand away from the Fiero as you lower the hydraulic jack. You will see the spring bow as the arm goes beyond it's normal travel. Now, mine didn't 'spring out' when it got all the way down (that seems dangerous, huh?) oh no, it was stuck. I wound up getting a shovel handle putting it against the lower a-arm and whacking it with a hammer all the while terrified the spring was going to get me. This is probably dangerous so you may want to chain the spring to the a-arm so it won't come loose when this happens. Maybe I'm lucky. That thing came off with a loud "BOING" and just hung there...
Now pull the bolts out fo the a-arm (remember how they go together) and remove the a-arm. You'll have to find a shop who can remove and install the ball joint using and arbor press. The bushings might require burning out to remove them. I'd stay with rubber replacements unless you won't drive the car long distances and don't mind noise in the front end. Polyurethane bushings can increase the vibration sent through the steering system and they tend to squeak over time. You'll have to clean the a-arms up some, maybe paint them.
Now to get the springs off, I wound up pushing on the bottom of the spring with my foot while using a crowbar to pry the top out of the suspension crossmember. It was a little bit of a struggle to get it out. Cut the bottom of the coil since the top is slightly tapered.
That's where I'm at, since I am getting Tie rods, ball joints poly ball joint/tie rod covers to replace the rubber and torn ones and I haven't got the new bushings in the a-arm yet. I expect the springs will be a little easier to get back on since they will be shorter. New shocks, bushings, brakes, tie rods and ball joints are going to go a long way towards a better riding car!
I'd consult with he Haynes manual on this procedure in case I overloooked or failed to mention anything.
Black 85 SE, undergoing work as we speak!