Hurst/Airheart, a leading manufacturer of racing brakes, tested the OEM Pantera brakes back in the 1970s. The first stop from 60 mph required 219 feet and 225 pounds of pedal effort, which is an extremely high amount of pedal effort. With each consecutive stop both the braking distance and the pedal effort decreased. Upon the eighth consecutive stop the Pantera achieved its advertised stopping distance of 133 feet (from 60 mph), and pedal effort had fallen to 115 pounds. Of course, in a “real world” situation such as a “panic stop” a driver does not have the opportunity to “pre-heat” the brakes with seven practice stops.
As the test progressed brake-fade set-in with the next (ninth) consecutive stop. There was therefore a fine line between optimum braking performance and the on-set of brake fade. One last point I wish to mention, Hurst/Airheart concluded from their test that a Pantera’s ultimate stopping capability had the peculiar trait of being limited by the brakes, rather than being limited by the amount of traction provided by the tires (PI News, volume 3, no.4, pages 27-32).
Citing this test, Pantera International’s founder Fred Matsumoto referred to performing a panic stop with the Pantera’s OEM brakes as a religious effort; he wrote you stomp on the brake pedal and PRAY that you stop in time (PI News, volume 14, no.2, page 14)! 
It befuddles me that these are the same brakes that some magazine testers praised, in fact one tester described them as “the best production car brakes in the world” (Motor Trend, March 1972, page 106).
Doug, be mindful of the fact that your GT5 is equipped with the same brakes as the Group 3 racing Panteras, the brakes are quite a bit better off than those fitted to the Ford Era narrow body versions.