I have the Tein type flex coilovers, only problem is i was not exactly impressed with the way my Z handles now. I'm coming from off road vehicle experience so work with for a sec. Can i take the springs from the type flexs and swap them out with a different spring without any major problems. Will this cause a rapid deterioration of the shock if a spring that is about 75% stiffer than stock is swapped in? or is this not even possible due to the way Tein manufactures its products? thanks.