Clunks and clicks when moving slowly (parking) on close to full lock on my 2003 X5 sport 3.0d was the anti-roll (sway) bar moving sidways. I replace the mounting bushes (mounts to the chassis) cost in UK £25 for parts and about 1 hour labour. I have been told by an indepentant BMW service engineer that this is VERY common on X5's. If you get the noise when going over bumps then it is the sway bar links as well.