suspension tuning

good day,
have a set of JIC coilover for my cefiro A31, they came from sylvia S13s. problem is, the spring rate doesnt match the cefiro since the cefiro has bigger body and heavier engine. i have rb25det in it.
i like the set-up to be street and tracks

if anyone can help me set-up my suspension?
any help would be appreciated

thanks

Unfortunately, you will need new springs to solve the problem. The springs you currently have are compressing to much under the heavier load, which will eventually stuff your shock absorbers...
Find what spring rate is recommended for a R33 skyline with coil-overs and have some similiar rate springs made to suit. The shock absorbers will need to be adjusted to give best performance.
Good luck...