The differences between the two are I fusion vs A Fusion strap (more material and stiffer on the A fusion) and a Nylon vs and oversized asymmetrical Composite Fiber Support panel (again stiffer with more material). The support panel only makes up the top third of the highback.
Riders who love a stiff binding will love the RS. The strap and highback shaping is really refined so while they are stiff, they are also very comfortable for riders who love stiff.
thanks, i think im going to get the rs's