One of the most overlooked parts of a car during modification, yet arguably the most important. We typically recommend brake upgrades as the very first components to tackle when getting into modifying cars. A proper braking system should be more capable than the limits of your chassis, drivetrain, and own personal driving skills. Nothing is worse or more dangerous than surpassing the limits and not being prepared for what follows.
The basics of braking systems have not changed much since ABS started becoming popular. Computers have become far more advanced over time, but the mechanics and hydraulics of a modern disc braking system are mostly the same sort of parts. You still have a master cylinder at the top, connected to the brake pedal. Along with the brake booster, this provides incredibly high amount of hydraulic pressure in the lines that go to a caliper on each wheel (sometimes a floating caliper, sometimes fixed caliper), which work together in careful proportion to slow and stop your vehicle
More exotic materials (silicon carbide, carbon brakes, etc.) are becoming more prevalent and obtainable for the hardcore enthusiast racer, which are helping reduce brake fade, increase performance, and provide significant unsprung weight reduction. Who knew that a fancy set of brakes could actually make you go faster?!