PSR spec front strut coils springs are manufactured to the highest standards in Australia by King Springs to our specifications. After many years of testing combinations we have found linear rate to be far superior to the widely advertised tapered wire that is "sold" at a higher cost to be an advantage.
Linear rate has a lower solid height than tapered wire and you will find before the coil is at its loaded (working) height most if not all the variable rate will be "solid" and not working as advertised. This reduction in wire diameter can also cause other issues such as walking of the coil where the coil moves on the thinner winds and also cutting into the strut mount insulator causing premature failure of the top mount.
Don't hesitate to contact us to discuss the correct rate to suit your needs! PSR spec coils are a platinum option and come with a lifetime warranty*.