Not to contradict my friend Jub, but Pfadt has changed quite a bit and are owned by AFE. They are a problem coil over. My friend just bought the new design and has had to warranty them two times with blown seals. Not a lot of miles either. They are always for sale used and there is a reason. In the HPDE world they are not high on the list. After much research and talking with many at the track, the tried and true brand I chose is LG motorsports. They ask many questions when you order and custom tune the shock to the spring rate for your car. I have the sways and their coil overs and the performance is unbelievable. If your not looking for HPDE performance KW's are fine.