Well. its not having higher spring rates than the front. What it is is having a higher rearward BIAS in spring rate. Remember that 75% or more of the weight in your car is over the front wheels. So if stock is like 4/1 it needs to be modified to like 5/3 or something, getting the ratio between the two to be more level.

Just get Tien Basics.. They can be rebuilt in the US for cheap, will work on your application, and are simple.