The white springs are a bit stiffer than the red springs....I have not looked for any other springs since the white are working so well on my nemesis.I have heard the blue matrix rear springs will fit the nem/gen shock bodies but dont know how the compare to white and red. You will need 4 sets of the Matrix rear springs to complete all 8 shocks..I dont know of an after market spring that will fit these shocks...someone else might tho..