what do you guys mean by "rough"? that it bounces a lot..??
thanks guys this really helped a lot.
'rough' is relative (your celica already rides more 'rough' than a cadillac does).
basically 'rough' is a desription of how much your springs give. (more give = smooth. and less give = rough).
the stiffer a spring is the rougher your ride will be. so saying, as a rule of thumb, shorter springs must be stiffer (so your car doesnt bounce on the ground among other obvious reason). therefore, since eibach springs are shorter (lower your car) they must be stiffer. this makes your ride more 'rough'