New turbo has a loud clackety-clack at idle that I don't remember hearing before first service at 2,000 miles. The car has never been abused, in fact, underutilized! I've heard that flat sixes have noisy valves but it's unnerving. No performance trouble, can't hear it when driving. Only 2,600 miles now. Been running it hard lately, but sound preceded that. Anyone with similar experience? I hesitate to compare to my C4S since that engines are so different.