My .02 cents (Again). I keep seeing these brake/caliper threads....... you really do not need to change anything with the brakes.
1. 4 pot Wilwoods front and rear (kit). (12" rotors)
2. Wilwoods are extremely light over the stock stuff.
3. Save your money and do not get the bigger brakes.
4. Do not overthink the brakes, the car is light, and my 818R is heavier than any street 818S (minimum race class weight with me in it (HP/WT) 2266 pounds).

I mated these up with Raybestos ST46 pads(or ST43 cant remember right now). Braking is really, really good (130 mph+ to 40mph many times). I adjusted them with my dash mounted bias control.