88siluder

Hello all, I am new here so please dont flame me if this topic has been covered somewhere else. I bought a suspension kit from Tokico (springs and gas shocks). The write-ups I have seen all show cutting the bumpers in half. Is this necessary? What exactly does cutting the bumpers do? Does that wind up lowering the car more? I bought this kit because they advertised that this kit was a 'mild' drop (about 1") which is all I would want. These cars are already low enough in my opinion, just want a smoother ride. Anyway, the kit seems straight forward enough, I will rent the spring compressor from Autozone just a little confused about the bumpers. Anyone had any experience with this kit? Thank you in advance. By the way, this is going in an '88 si.