Both are the same. The 16" wheel is steel which is heavier and causes the weight to be the same as a larger alloy wheel.
It's the tires that get you. Tires for 16" wheels are mostly LT D and E which is very heavy and hurts performance. 16" wheels are the LAST wheels I'll run from now on.
I'd do 15s, 17s, 18s, or 20s in that order if I had options.