Swift made Sport Springs Spec-R is made for true track racing enthusiasts that wants to take their vehicle to the next level. Sport Springs Spec-R is engineered with 2 main characteristics. 1 Redesign lowering ride height to maximize the suspension performance allowing the vehicle to fully absorb road condition for maximum traction. 2 Increase in spring rate to further enhance cornering speed through entry & exit. The increase in spring rate is based on the vehicle factory stock valving settings. Sport Springs Spec-R is increase to the optimal rate that the stock shocks can handle. Higher performance shocks are not required, but recommended. Spec R springs are wound with the same engineering as our sports springs. With the exception of stiffer rates and slight change in ride height; you can expect the same characteristics as our sports springs.