Shock spring compressor? Hmm... well, one can buy them for around 400 dollars at the nice end - 75 dollars (US) for a hand winding one... BUT, we just make them.
...mine and Radar's are like the GP Racing unit, made from scrap metal (free) and put together using one of our bottle jacks and various different sized rings to act as collars. Otherwise a generic engineering hydraulic press with a couple of blocks and a mildly customised bearing splitter will do it far better than some of those hook onto the spring and tighten nuts n bolts jobs I have seen out there...