beleive the skunk2 street coilover kit is 500/500 but I could be wrong... Spring rating is what the particular spring coil was headed too... the larger the spring rating the stiffer the spring. You sure you don't have the Skunk2 Drag Launch kit? What koni struts do you have? I personally have the Ground Control Coilover kit (custom spring rates are available with GC's btw) with Koni Yellow struts. Car rights stiff/firm (I have my settings set at maybe half in front and maybe a 1/4 streigth in back) but not bumpy as hell stiff. Also, how dropped are you? The lower you lower your car obviously the rougher the ride will be cause the strut doesn't have as much room to absorb shock.