Yep, definitely pricey, but have you seen the only other option available? Carbon Ceramic Brake KitYes those rotors are way cool but they are also way expensive at over $900. They'd have to be seriously light to be worth that much. On the upside unless you're racing the car they should last a really long time.
I think that's just the way it's going to be until more companies get on board with Model 3 upgrades.