Well an aux cooler won't hurt with auto. Mines a 5 speed manual so I did more down shifting. As far as brakes if your going to do it on the reg basis brake box is a good idea. But if I remember right the brake sys on extended cab is raited for close to 8,ooo gvw. Just make sure you have plenty of meat on the pads.
drag racers prayer, "As I lay rubber down the street. I pray for traction I can keep. But if I spin and start to slide. Please dear god protect my sweet ride". Family truck'ster