Big brake kits look fast and promise better stopping, so it is natural to assume bigger brakes stop you shorter. For a single stop from speed, that is mostly a myth. The real benefit of larger brakes is different - and worth understanding before you spend. Here is the truth.
One stop is limited by tires, not brake size
Your stock brakes can already lock the wheels or trigger ABS on one hard stop - meaning they can apply more braking than the tires can grip; see does tire size affect braking. Since grip is the limit, adding bigger brakes does not shorten that first stop. The tire is the bottleneck, not the caliper.
The real benefit: heat capacity
Where big brakes shine is repeated hard stops. Braking makes heat - see how hot brakes get - and small brakes overheat and fade under sustained abuse. Larger rotors and multi-piston calipers absorb and shed far more heat, so they resist brake fade lap after lap or down a long mountain. That is why track cars and tow rigs use them.
Who actually needs them
Track days, heavy towing, mountain descents, and much heavier wheels/tires justify a brake upgrade. For normal commuting, a bigger brake kit adds cost and unsprung weight with no shorter everyday stops. Better tires and quality pads give more real-world benefit for most drivers.
Smarter upgrades first
Before big brakes, upgrade tires, fit a quality performance pad, use fresh high-boiling-point fluid, and ensure good rotors - see best pads for towing. Those cheaper steps fix most stopping complaints. Quality pads and fresh hardware beat oversized brakes for the street.