Tires, wheels, springs, shocks, sway bars and rubber suspension bushings can all be upgraded, to help the truck better carry the weight, in an overloaded situation. I have done all of these on a few of my trucks.
There is very little that can be done with the brakes to make them work significantly better. Drilled/vented rotors can help them not fade as much during repeated braking. Different pads/shoes can be used too, for a small improvement in braking, or for longer wearing. However, none of this does much to truly significantly help braking ability.
Aside from swapping in another axle from a bigger truck, with bigger brakes on it, you're stuck with whatever the truck was made with. And therein lies the main problem with running a truck overloaded: Poor braking ability.
This is a major reason why I decided I was done with driving overloaded F350's and got a truck with significantly bigger brakes (after one of my F350's was destroyed in a fire). I got a class 7 commercial truck, and loaded it to significantly less than it's 33,000 GVWR, while also quite a bit heavier than F350 could ever hope to carry. It weighs 20,000 lbs and stops on a dime. :)
