In a car with disc brakes, the performances (how long it takes to brake, how many braking cycles can be performed without overheating, brake power before locking the tires, and so on) depend basically on tires, brake discs, brake pads.
In theory friction between two objects only depends on the friction coefficient and on the force, not on the contact pressure, so narrow and wide tires should be equal (the weight of the car is the same), but in fact the rubber in narrow tire (besides getting worn out faster) will heat more, potentially limiting the performances.
I think that bigger discs will cool down faster, but I don't know how and in which cases this affects braking performances.
Bigger or multiple pads... besides lasting longer, I'm not sure.
So, in what are each of these three elements limiting the braking performances? for a given car, what will I obtain if I mount wider tires? (I think the radius won't matter much). What about larger discs? or (hypothetically) bigger pads or multiple pads?