To clarify, I meant solid as in round poly bushings vs. the MeyleHD bushings which although are constructed of solid rubber, are not solid in the sense that they have channels for movement; just as the OEM has channels. I am sure the OEM style rubber is also softer then solid poly. I didn't notice much (if any) change in comfort going from OEM style to MeyleHD. I would think this is not the case when going Poly or Monoball.

Poly:



Monoball:



MeyleHD:



Fluid Filled OEM: