No, they are not adjustable, they are the same as genuine Holden ones. If you have the original bushes on there at moment it's just a matter of remove and replace. Undo the big nut on the radius rod ( it will be hard to undo) then undo the 4 small nuts that hold the bush to the crossmember. Pull the bush out and put the new one in. The big nut on the radius rod should be done up to 140-155 Nm. I found it very difficult to get the correct torque lying under the car with little room to move, so I just did them up as tight as I could. It would be easier to get the correct torque with the car on a hoist.