Couple of things. I'm a HD mechanic so hydraulics are what I do. That caliper have increased area meaning more force with original pressure. Changing the master cylinder (which is a simple pump) to one that can produce more pressure will cause more force on a stock system. So if you add the two together piston size and pressure produced equals a lot more force. So much force that those calipers were not designed to handle. The web site says that they removed material for weight and increased webbing for support. Less material = weaker No mater how much webbing they put in it will never equal the material removed. In a stock application no problem. So I'm saying a combo of weaker calipers and to much pressure.
Not to bust your balls Pontiacgp, as for the 2000psi brakes, no way. Banjo fitting won't handle that. That build safety factors into brake lines and tubes but not that big of one. Most excavators, dozers etc only run pressures of 2500psi. And the hoses used are as thick walled as car brake hoses are wide in diameter. So yes you have more pressure but not 2000psi