Adjust what? You CAN NOT adjust the spring rate as that is the actual stiffness of the spring that came with the shocks.
What you CAN adjust is the damping rate, if you got one of those shocks with the adjustable damping rate dail on top of the shock.
If you have really stiff springs, say 10kg spring, no amount of damping is going to be able to compensate for the harshness.
To find out what spring rate your current coilovers have, go to
http://www.skylinesaustralia.com/forums/Sp...Are-t79157.html
and follow the instructions.
Btw, when I said 6/5...etc. I mean 6KG spring for the front coilovers and 5KG spring for the rear. Not the damping adjustment dail on your coilovers, if you got those.