Of all the parts on your vehicle, brakes are the most safety-critical. This is one area where genuine OEM is not a preference but a necessity.
Brake Pad Compound Specifications
OEM brake pads are formulated to specific friction coefficients matched to the vehicle brake bias and ABS calibration. A pad with a different friction coefficient may cause the ABS to intervene differently than intended.
Brake Disc Metallurgy
Brake discs must be manufactured from the correct grade of cast iron to match OEM thermal characteristics. Cheap aftermarket discs can develop hot spots and warp under repeated heavy braking.