If you were shopping for the Toyoyta 86, 2016 vs 2017, I would get the 2016 while you still can!!! Run to the dealership!!! haha
However since it's the BRZ, Subaru did a great job not screwing up the exterior looks so I would just get the 2017 especially since they are coming in September.
Unless you really want one now, than you could just get a 2016