I dunno about you guys, but I think the brakes are fine. Sure, my truck doesn't have 600 hp, but what are the real differences?
600 hp doesn't really change how fast you can go. The stock brakes will bring you down from 100 mph plenty quick.
600 hp may mean you're stopping from higher speeds more frequently. So is brake fade the issue? I feel like I've hammered my brakes pretty well, and I've never felt even a hint of fade.
Our brakes were designed for towing situations. I think you'll still have plenty of margin with a 600 hp engine out in the desert. To be fair, though, perhaps you shouldn't test near the grand canyon.