Spring Compressor Q...

do you need an impact tool to use a macpherson style spring compressor?

Not neccessarily - but 1/2" drive ratchet will give you better leverage than a 3/8 drive. YOu need leverage. The best thing that pneumatic tools are good for is speed. You DONT want speed when squeezing a spring. You want to go slowly and listen for sounds telling you that your spring compressor is about to bust apart cuz you installed it wrong.