[racing] XJS spring specs?

i realise this is a very old thread! i am in the process of making my 4.0 sportspack (thicker ARB’s) xjs a “safari rally” style car, and am at the stage where i am looking at springs, front and rear. i will be using gaz front and height adjustable rear. i want to increase ride height, and am considering for the front to use the v12 springs, and convertible springs for the rear. as they are designed to accomodate a larger weight the car would sit higher, which is what i desire. however i don’t understand the physics behind spring rates, so am concerned that the ride would be very stiff. essentially i want to gain ride height, and have a “progressive” spring, so the car is not rolling all over the place, but equally a certain level of comfort is achieved when off road. can anyone chime in with a suggested spring set up? any help greatly appreciated :slight_smile: