Thats what happens when you get a "light" colored car and paint straight onto plastic without any primer. Hopefully GM will learn to start doing it or have TONS of warranty paint repairs.
As for the idle, its just the nature of a small block pushrod V8 from GM. My LS1 shakes a good bit at idle and every other LS equipped car Ive seen and been in does the exact same. Enjoy it as its literally the heartbeat of the car.