I'm guessing you have an 8 lug since you said hub and rotor as 1 piece, but 2500's could be 6 or 8. 1 upgrade you can do is to replace your front brakes with 3500 DRW stuff. The dual rear wheel rotors are a 1/4" thicker than the 3500 single rear wheel and 2500 8 lugs. You'll also have to do the calipers to work with the thicker rotors, and use the matching DRW pads. Depending on your rear brakes, you may have some options there as well. If you have the 13" drums, you can always swap in a set of the DRW 1 3/16" wheel cylinders instead of the 1" or 1 1/16" ones that the stock 13" single rear wheel trucks came with. These upgrades make a NOTICEABLE difference in braking, but it still isn't going to be as strong as the newer brakes are, but it is ALOT cheaper to do than the newer stuff. Again though, without knowing what you have exactly, theres not much advice we can provide as GM used ALOT of different braking options.