I would recommend getting Teins instead of K-Sport/D2 for every day use since they dont have potholes and such on tracks. Dont know the prices in the US but i can get Teins from U.K for almost the same price as K-Sport/D2 in Norway :)
Teins have some coilovers designed for street use so they last longer since they are softer on the softest settings among other things :)
If u live where they have good roads and ur on a track on regular basis they would do just fine :)
Over here it so bad roads on the west coast of Norway so Teins would make things better for me :) Gonna overhaul my set of K-Sports and then sell em and get Tein with EDFC :)