Thanks ABNo experience myself with this kit. Unless you car is equipped with a full cage etc, I'm not sure if they will add something noticeably extra over the KW V3, as no body-roll adjustability in the Cup system.
(only real difference if I read it correctly is the choice of springs: kg/cm pressure; as they mention competition springs, but as they have the same diameter as the V3 springs..)
If you want something better then V3, going to full race suspension it probably more worthwhile: also body roll will then become adjustable for example.
Lot of choice in that area too.
To me, without a welded cage and welding the car, going to much stiffer stiffer suspension is not really usefull: the car is not stiff enough to fully enjoy it.
My 2 cents