Taking the A arm horiz type bushes,the rubber bush is bonded to the shell of the a arm bush on the outside and the pivot pin on the insid,the bushes are fitted so that whan the car is at 'normal' ride height there is little torsional stress on the rubber bushes,as the the suspension goes up/down the rubber in the bush is used to resist the twist,in fact it helps the 'spring of the suspenion.If the ride height is lowered the bushes are put under torsional shear loads at the new 'normal' height...and can cause early wear on stock bushes.If you check the 'book of words' you will find on the rear suspension,that the bushing thru bolts should not be fully tightened until the vehicle is on the ground with the weight acting on the bushes before they are 'locked' to both the moving & fixed part of the suspension...,rubber bushes only have a limited torsional movement range ,which is why we dont set them tight until the vehicle is at correct ride height....
