So drive about half the time in sport. Not too hard. Not too soft. For about 3 days, I was occassionally hearing a faint to medium volume 'clank' ever so often and mostly in sport. With all the problems posted on here.....I started running down the list mentally thinking engine, transmission, driveline, etc.....running with radio off, air off, windows up, windows down. Then once when it happened it sounded like coming from back seat. Next stop I found my first 'problem'....the Mrs. put two full wine bottles in the rear underseat storage container and put a towel over them....problem solved. Paranoid much?