There are a lot of suppliers of bits and pieces. You can make your own pretty easily. Try
http://www.stockcarproducts.com/Look under Carrera Shocks and see the coilover kits. Oh! tell them it's for your stock car not the street
Basically it's just a sleeve, top and bottom spring holder and a spring.
I'll look for the PFF build later.
*edit*
Here is Steve Hoberg's thread.
http://www.fiero.nl/forum/Forum2/HTML/046456.html***
I got a set from Jonathon McCreery, but not sure if I'll go that route. You can cut the perch off of the strut and mount the coilover from the bottom. Or you can trim the sleeve to fit the perch and use a shorter spring.
I'll try to get some pics of mine tonight as they are not mounted (like everything else).
Gary