I have a 2011 model and I'm 99% sure that 16s will not fit.
I haven't personally tried it is why I won't say 100%.
I run 18s on the street and I run 17s at the track.
With the 17" wheels there is tad bit less than an 1/8" of clearance between wheel and brakes.
This is with GM stock 5 star 17" wheels.