oic, thanks a lot. The dual means two difference faces of the piston that in order to provide a different compress and rebound speed. Right?
But what is the advantage of the car when actually run on the track? E.g. does this piston provide better landing when jumping? and provide better reaction when the shock rebound?
Yup, taper piston normally will provide a different compress and rebound speed depends on which direction you install the piston. Technically, you can have harder compress with relatively softer rebound or the other way round. With normal piston, compress and rebound rate are always the same, which are control by the viscosity of the shocks oil you are using.