The 918's braking system is smarter and more complicated than your first car.
As with any hybrid, the 918's brakes have to do multiple jobs—stop the car, yes, but also blend in the regenerative (recharging) needs of the car's battery pack, incorporate functional ABS and stability-control systems, and feel something like normal in the process. Porsches are known for absolutely fantastic brake feel—a rock-solid pedal under all conditions, with little travel and great feel—and the 918's engineers claim that making the car's brakes behave like Porsche brakes was one of the most difficult parts of development. The system is electrically assisted, with a complicated assist servo mounted between the firewall/brake pedal and brake master cylinder. The servo is unique in the hybrid world, with the goal being to maintain an unbroken mechanical link between your foot and the car's hydraulic system.
There's also something the engineers could only call a "fluid capacitor" mounted in the car's nose. (Translation difficulties abounded during the launch; a lot of the technology on the 918 was dreamed up for the car by German engineers and thus has no direct correlation in English.) Below 0.5 g of braking force, the car uses its electric motors in regen capacity to recharge the battery pack. Above 0.5 g, it doesn't. The so-called capacitor, as its name implies, serves as a fluid reservoir that helps bridge the gap in mode change, allowing pedal feel to remain consistent and predictable no matter what the car is doing. It does, though you can occasionally sense some pedal weirdness around town, as if the car is trying to second-guess your intentions. But it's a monumental achievement because the brakes feel largely natural.
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