The compressor is for both removal and installation. The first spring was a little tricky because my Dad and I had to get used to indexing the spring cups in order to actually get the spring out once it was compressed. Once that one was done they rest went smooth. Just make sure when installing the new springs that they are seated correctly in both the insulator and lower control arms. Otherwise you will get a crooked ride height.

The pads are spring insulators and go up inside the spring pockets in order to prevent metal to metal contact. They also serve as ride height adjustments too because of the different thicknesses offered. Attached is an exploded view showing the highlighted spring pad.