My new 13 SEL began making thumps and rattles after having it 2 months. Speed bumps, entrances to driveways, tight turns all caused the noises, but they were intermittent and did not happen every time. I intentionally waited until the noises were mostly reliable before taking it in. First trip to the dealer resulted in "sorry, but we couldn't hear anything but normal suspension noise". Seriously? This car is so quiet that you can hear the slightest of noises, but I've never had a car make any noise in the suspension other than the swish of oil through the shocks.
Fortunately for me, the left front strut oil seals began to leak and evidence was now on the inside of the front rim, and the noises increased to all the time. Second trip to a different dealer was met with "your left front strut needs to be replaced- I've ordered the part and we'll replace it next week".
Done. I'm not crazy, and now it makes no noise at all. My first thoughts were sway bar bushings because of occasional "thumps", but it was the strut.