The differences between this car and the RR is the pivot mounting location(center and side), shock location, flex plate design, pivot design,Wheelbase change,color change,flex plate height and mounting change,Its lighter and more rigid,and more narrow. The car is designed for the 1S LiPo batteries. The new suspension was changed around the difference in weight placement that we have over the 4 cell cars. Less weight required a different suspension layout.