Man, I would have it thoroughly checked out for sure by a Mercedes mechanic. Did you get a warranty? How did you find out it was a track experience car? 110 miles? I thought they kept those for 3000 miles or so. This is one reason I'm glad my car had 10k on it when I bought it with a history of a normal driver, well more normal than an SRT car.

The brake noise could be from rust after the long haul. If it doesn't quickly go away, it's probably the tattle tales in the pads meaning that you need new brake pads.

Just remember that these cars were built for hard driving. It may have had a rough beginning, but it should be fine for a while.