I had the exact same noise when going up my driveway. It was a bolt on the subframe crossbar that needed tightening. There are 4 crossbars. 2 that go from the center front under engine) to sides (between front and rear wheel), and 2 that go from center rear to sides, 2 bolts per crossbar. All you need is a torx bolt socket. Easy fix. Note: I have a convertible. I'm assuming the coupes have these crossbars as well.