I don't really have many realistic "wishes" for the BRZ. Someone mentioned factory camber adjustability, and that's definitely a good one. Other than that, different head-unit and door cards that don't rattle when the speakers are turned on would have been nice. And a proper, high-mounted third brake light instead of the big one at the bottom that blocks the rear view.
Oh, and one of these in place of that redundant, illegible, useless speedometer:
Most of the other flat engined things I use have them, and I'm really used to consulting them on a regular basis. I like to be nice to my engines and let them warm up properly before giving them a workout, so having to guess when my oil has warmed up in the BRZ is always a little annoying. It's particularly annoying given the cluster space they essentially wasted on that analog speedo. I literally never look at the analog one since the digital one in the tach is so much clearer and more useful.
A way to deactivate or at least modulate the power steering assist could be cool. I run modest tyres and am kind of used to driving cars without power steering, so it could be nice to at least dial the assist back a bit for a little more feedback.
Unrealistic wishes? Somehow make the engine sound like a flat six? The sound of the flat four just isn't as nice as a six, although I guess even Porsche's sportscars won't make that howling sound for much longer