Hi ,had the same rear clatter over lumpy road,after numerous checks , turned out to be the front ball joint on item 8 control arm , replaced it, clatter gone.
However after much thought perhaps I could have reset the old parts by rotating the front ball bush 90 deg (as it only takes linear fore and aft thrust), thus presenting unworn surfaces, worth a try at no cost ?
To clarify, after removing the control arm, mark the round flat clamping face of the front ball joint (bush) scribe a line at 12 and 6 o'clock or use white out pen, then with fingers or pliers turn the bearing mark 90 deg to 3 and 9 o'clock position (don't damage the rubber boot) and reassemble.
Boxter
Linear Mode
