If you are getting “impact” thumps or knocks as you put it. Have a good look for tell tale marks on the wood where the axle comes through into the wheel well/arch. Some cars have to have a little of the wood removed. Also on some cars the drive shaft hits the tunnel edge. Wolfe performance would check all of that if they fit the shocks for you. Have a chat to Cain, think you will find his experience of sorting out suspension is really interesting & enlightening. ( am just a satisfied customer of Wolf)