I do not have the brake pedal ratio, master cylinder size, or brake booster assist.
I’m going to input a 6:1 pedal ratio because that’s a common manual brake ratio and I am familiar with leg effort numbers here. This will also be so I can leave the booster assist numbers out of the equation. There is a 27 stamped on the master, which I am going to assume is the bore size in mm. It falls inline with other power brake master cylinder bore sizes. Master bore size, pedal ratio, brake pad coefficient of friction, and brake pad height are constants in these calcs, so we can get a fair assessment of what will change with just changing the caliper and rotor.
50lb input on the brake pedal, with stock caliper and rotor (315mm): 917 lb/ft torque
50lb input on the brake pedal with the 8 piston and stock size rotor: 853 lb/ft torque
50lb input on the brake pedal with the 8 piston and 350mm rotor: 964 lb/ft torque
47.5lb input on the pedal with 8 piston and 350mm rotor: 916 lb/ft torque
So forget the torque numbers as a rating, but use them as a comparison. On paper, a mildly stiffer brake pedal would net slightly better braking tq with only a slight change in bias front to rear.