I have Nex Coilover and the front is stiffer than stock.. thats ok but tjhe back is really soft. My question is if i get higher spring rates willl that make it stiffen up? ( i do not kno wwhat spring rates are on there) it has maxspeed spring it says 180060 07/06 something like that on the spring.

 

You need to know the spring rates. Thats one of the first things to know when buying any suspension part.

 

Without spring rates, you're only asking for conjecture. Most likely, your rear spring rates are lower than your fronts which is generally incorrect for Evos.