Martin, adding a back up camera is always a great idea. as a 350Z owner, I didn't have any problem backing out in my 370Z. But I did feel a little nervous due to thicker rear quarter panel (slightly less visibility) in the 370z. So, I recently added an aftermarket nav and a rear view cam.
The cam I bought was not expansive at all and works pretty well. I was going for the JDM look as far as cam goes and here are the pictures
JDM rear view cam (Japanese option. Not available in U.S.)
Mine
Socal 370Z is looking into another option which is Gentex back up camera. YOu can read about it here
Gentex Backup Camera and Mirror Video