I have 2001 4.4 with SP. I was sketical of ride quality with lowering spring and got feedback from TommyX. I finally had a BMW mechanic to put on Eibach front spring and he also used DIS to lower rear height for it has air-suspension on the rear. After 3000 miles or so, I like Eibach and the ride is not rougher than original SP. I have no regret with Eibach front spring.