1. Stopping distance is ultimately limited only and exclusively by tire friction on the road.
2. Any car with stock cool brakes is able to engage in an emergency stopping manouver of a fully loaded car to a point that exceeds the tire friction limits (i.e. locking tires).
3. The sensitivity of the brake pedal along its travel path, or the strength of braking under initial and moderate pressure on the brake pedal has ZERO impact on the minimum stopping distance.
Corollary 1: If you can apply sufficient braking pressure so as to lock the tires / engage the ABS, you've exceeded the maximum grip of tires on the surface. In this situation. which is true for 100% of stock cars, NO brake upgrades WHATSOEVER will change your braking distance over that single event.
Corollary 2: No matter if your brakes feel weak or strong, no matter whether you need to feather the pedal or slam it, if you can ABS/lock the tires, your minimal braking distance remains the same
Corollary 3: If your brake system is able to ABS/lock the tires, the ONLY improvement of braking distances can be acheived by having better tires
4: All of the above assumed a single braking event. For REPEATED braking episodes, heat dissipation of the brakes as well as their ability to function properly comes into play. Whereas ALL cars can acheive minimum stopping ranges under a SINGLE emergency stop, the subsequent braking response for repeated events (i.e on a track ) will vary.
5. Overheated brakes lose their braking ability
Corollary 4: In a situation involving repeated braking, the heat dissipation of brake systems at some point will be insufficient to properly cool the brakes down in between each braking sequence.
Thus, a point will be reached where the effect of heat WILL degrade the performance of the brakes to the point that they will be UNABLE to reach maximum tire grip. In this, and this situation only, the braking distance will increase, being limited by brakes and not the tires. This is also where "brake upgrades" are justified.