Shorter sidewall tires will usually increase ride harshness. The bushings on the 560s are tuned for the relatively flexible sidewalls of the 65 series tires that will damp out most of the high frequency road input.

I recall riding in the back of a friend's 560SEL some years ago - OE size tires - and was suprised at the ride harshness. The damping felt okay, but you could feel/hear every thump in the road. It was like the rear of the car was riding on wooden wheels! I guessed it was somewhat attributable to the semi-traling arm rear suspension on the 126s. The multilinks in the 201s and 124s certainly don't transmit anywhere near that kind of harshness.

Duke