Panic I will admit when I have a full 2-4k load the trucks brakes feel weak compared to normal driving with no load. BTW my Loadmaster is a 1.5ton with low gear 6.17:1 so if Im doing 45mph my 235 is running 3000+RPM and the truck does not handle like a sports car.
You can upgraded the brakes, suspension, motor, etc, it all depends what you want the end result to be. I wanted a close to stock mechanically restored dependable driver, so the rebuilt factory brake system is fine for my requirements.