There is a quite a difference in feel from a rotating cast wheel to a forged wheel. weight spins and creates rotational forces. Some are good, some not so good in reaction.
So the cast wheel rotor is different from the forged and carbon version wheels. You might check braketech website and see if they have the K67 cast wheel rotors for sale yet. They just released the forged and carbon wheel versions late last year.
You work your way to spending alot of money on the braking system. Get the calipers first is fine. Get the rotors for the cast if you think you can live with that rotation weight. I would get the forged wheels first and even just use the OEM rotors for bit, then the rotors upgrade can be several companies now offer for the K67 forged and carbon wheels. I have 3 different brands now. Alpha 6mm, BrakeTech 6mm, and now TK Dischi freno 6mm