Unlike old technology Poly bushes any increase in vibration / harshness felt through the vehicle is normally undetectable. Bushes are one of the most highly stressed components fitted to a car. They undergo enormous strain, in the most arduous of conditions with no maintenance or lubrication.
As the title states I've always had this type of Polly Bush on my vehicle so much firmer than factory original bushes highly recommend for any car in which handles better on roads