I've been through this 100 times before. I have been selling suspensions for about 10 years (with diffrent companies and then for myself) One thing is I always see people climb the suspension ladder. usually Blues or GR-2 and crappy springs or coil over sleeves. and are unhappy, so buy better springs and Tokico Illumina, AGX or Koni/bilstein. then FINALLY break down and buy coilovers. when they would be best served buy just buying coilovers in the begining and rebuilding/revalving them if they wanted to change the behaviour of the car.

stock length dampers will never work well on a severly lowered car. since the bump stops are never plesent and not easy to control esp. at speed. and many will bash themselves to death when ran too low. a shortened body strut is the minimum for serious lowering which most cheap coilovers today are length adjustable, and allow the user to "grow" the suspension with the owner. (stiffer springs, more damping, double/single adjustment) now I can explain over lowering of strut based cars and roll center adjustment but I'll leave that for chassis and suspension forum.

Keep in mind "cosmetic" lowering and "performance" can differ significantly as I only deal with the later. even if it doesn't "slam" the car the best performance is always the goal.

If you want to take advice, even a cheap used set of coilovers is the way to go. I have rebuilt 2 S13 sets this week alone. and during a rebuild almost anything is possable, changing to adjustable, double. diffrent spring rates, etc can all make a HUGE diffrence.