I installed a Full Traction 3" lift with heavy duty front coils and a spring compressor was not needed. The rear was easier than the front. Just make sure you disconnect things like the brake line brackets (frame and caliper), locker wiring clips (if you have a Rubicon), sway bar links, breather tubes, etc. so you'll get the maximum amount of axle droop. Keep a jack under the differential to support the axle. Also, when you install the coil on the front driver side, for example, put a floor jack under the axle on the passenger side and jack it up. This will cause the driver side to drop way down so you can get the coil in. Vice versa for the passenger side coil. A pry bar will come in handy too.