question in title.

do i lower the spring or the shock?

 

Should be exact same as the front, turn the dial underneath the spring. . .

 

No you do not turn the dial under the spring in the front. You thread the lower mount up into the shock.

The rear you have to turn the dial under the spring because its not independent from a shock.

Messing with the dial in the front changes the preload and if its set from the factory changing it can make it ride really rough and cause the shock to bottom out. That can cause the shock to fail so just lower and raise it with the lower mount.