The rear suspension was converted to a coilover setup. The difference between coilovers and regular shock and spring combination is that the springs rest on a collar that is on a threaded tube. The spring collar and be adjusted up and down on the threaded tube to adjust the ride height.
The coilover conversion kit that I am using is from OPM Autosports. It took me 3 tries to get the right parts from them... the first kit they sent me wasn't even for the correct car! Note that coilovers kits and springs can come in different diameter sizes, commonly 2 1/2" or 1 7/8". I haven't heard of much of an argument for or against one size or the other. I am using a 1 7/8" kit because I got 3 sets of Carrera racing springs used, $20 a pair, and they are 1 7/8".
The kit should contain at a minimum the following pieces: The threaded coilover body, the spring collar, that threads onto the body, and an upper spring perch. Here is a picture of the kit:
Assembly is pretty simple. The only problem I had, and I have herd it is common on kits like this, even for other cars, is that there was a metal ring on the shock that was larder in diameter than the actual shock body, preventing the coilover body from sliding over the shock body. I simply ground away the metal with a bench grinder.
After this metal was ground away, I covered the bare metal with some white automotive touchup paint.
Then assemble all the parts of the kit and hope everything fits! Here is a picture of one side assembled and ready to bolt in.
Note the top spring perch isn't touching the spring. Once weight is put on the car, it should compress enough to touch. If not, you need to screw the lower perch/collar up on the coilover body to take up the slack. Also make sure that when it compresses, the upper perch goes into the middle of the spring.