the original rs4 was a belt drive with a totally different chassis now the rs4 3 evo and evo+ and rs4 2 are shaft driven and all will accept the 2speed
The RS4 2 is NOT shaft driven, the original RS4 and RS4 2 were nearly identicle with the exception of the pipe, and the original RS4 chassis was not annodized purple. The shaft driven models started with the RS4 3 RTR, since that first version they have basically remained unchanged as far as chassis, and suspension. The only things that have changed is the mill, pipe, and the tranny, all of which will drop right in to the RS4 3 RTR chassis.