yeh the only time it knocks when moving the exhaust about is if you really swing it, ive put some cable ties on the mounts to stiffen them up. Got dog bone mount insert coming next week going to put that in and see if that helps aswell. its passed its mot with it, been 4 wheel aligned and i had a really good look over it when it was on the ramps aswell, so thats 3 fully qualified and experienced mechanics that have looked at it and found nothing other than the exhaust knocking if you swing it side to side quite violently. and the small amount of play in dog bone mount