and the answer is ...
The service manager at my local MB dealership informed me yesterday that they think the source of both strange sounds is a defective wheel bearing. The good news - they intend to repair it under warranty. The bad news - they believe the car may have been wrecked at some prior time. They can't tell how bad the wreck was - but believe that the dealer I bought it from should not be held at fault because the body work was so well done that it is barely perceptible. I, on the under hand, am somewhat upset as I ran a carfax and my insurance company did a check and found no record of an accident or damage. I know the car was a MB lease program car before I bought it - would MB records show history of body work being done while on lease and does anybody know how I can get that info. Thanks