FWIW, Tire Rack gives 16" steelies as a Winter wheel/tire option only for non-PP '17 BRZ. For Performance Package it only gives 17" and 18" options.
https://www.tirerack.com/snow/Winter...odClar=Limited
I'm 90% about to buy a '17 PP BRZ, if I do probably get 17x7 wheels and 205/50-17 Pirelli Winter Sottozero 3s for it.