A: The BC coilovers are one of our best selling coilovers for the Solstice/Sky. They are a single adjustable coilover that allows you to adjust compression/rebound with a single knob located on top of the shock. The coilovers also have ride height adjustability with adjustable shock body length and also the spring perch is adjustable to allow you to adjust the preload on the spring. The KW variant 1's are not adjustable for compression rebound and do not have adjustable shock bodies, but do offer adjustable spring perches. The KW variant 3's do allow compression and rebound to be adjusted individually, however they do not have adjustable shock body length, but do offer adjustable spring perches. Hope that helps, let us know if there is anything else we can answer for you!