Having had the lower near side suspension arm replaced FOC I still have a slight knocking noise but much reduced and only usually noticeable on rough tracks and very poor and broken roads. My next line of attack was to do the cheap and hopefully simple things so I have orderded anti roll bar bushes and drop links for the front of my 2003 C320. I have changed drop links on other cars and remember having to support the anti roll bar to prevent it dropping. I presume the same applies to the C320? I was planning to soak the bolts etc in penetrating fluid for a few days first. The bushes look fairly simple, access is OK so it is take out two bolts, remove the saddle clamp then slide the bush out and rotate off, refitting is a reversal etc etc!