Hey Op. The shorter springs are going to go in the rear. They wont require any compressing and should easily sit on the Perch. Your longer springs of the set will go up front, you will need a spring compressor to get the OEM springs off and your new springs on. Read the DIY for the spring install, Its whats I used to do my GT-S spring install and had no real big issues. GL
DIY: 370Z Lowering Spring Install