A mock suppressor is typically only worth getting if you plan on installing an inner barrel that is longer than your outer barrel. Only get a light if you plan on playing in darker areas, otherwise you will be adding weight to the front end of your gun when you don't need to. As far as scopes go, you should not need a scope with any magnification on it, as the range of most airsoft guns does not require this. If you really want some kind of optics I would suggest a decent reflex sight. Real upgrades are going to be mainly internal. The easiest upgrades to perform are the installation of a tightbore inner barrel and a good hop-up bucking and chamber. The CM16 already comes with a pretty good bucking, but a better barrel will improve your groupings.