One thing that I have noticed over the years is that a lot of people assume that brakes are brakes. The same people who would not pick a random set of heads or camshaft for their engine will bolt random brakes on their car. The brakes need to be selected with as much care as the camshaft. The caliper bore sizes need to match the weight distribution of the car and the master cylinder bore size needs to match the caliper bore size. It is a hydraulic system and all of the piston sizes need to be carefully selected for correct operation. Most of the people I talk to have no idea what the piston size is in their calipers or the master cylinder. They just bought some cheap parts off the internet and bolted them on.