between 2000-5000 kms (some where in between those kms), spring rates are 10kg front and 8kg rear and I have a set of 5kg springs for the front! and the car handles faster with those, and ran 1 sec quicker around winton on with them on! aren't they come with 7kg front and 5kg rear spring with it? how come u have this set up on ur coilover? cause the cars cornering speed is quicker! i know it will get better cornering as it is a stiffer spring but wouldn't it be too stiff for the streets..