Explain.
Autocross is very quick aggressive pulses, there's not much beyond an even pedestrian brake compound couldn't do. As per usual tires would be a better buy. Hell, for the weight I'd go either stock or smaller discs with a low temperature compound for reduced weight. Your braking system can lock the tires up, the limiting factor is the tires/friction with the road. You're not going to be heating the braking hardware much due to low speeds/low braking time so there's not much you need to change. Hell, my track pads don't start to warm up until the 2nd or 3rd run.
Roadcourse? Pending roadcourse design there are a few brands/lines people like. You can get into the intricacies of how the braking force is applied or how grabby/progressive the compound are, progressive fade, etc. Stock summer pads aren't a bad pad and really any track focused pad will provide a better defence against fade, initial bite etc. The limiting factor you'll run into will be brake fluid (It will boil) and in my experience rotors. Personal favorires are Motul RBF 600/660 and Castrol fluid. I warped my stock rotors on my 2nd track day, but swapping to some cheap cryo-treated Centric blanks (Remember, pads and rotors are disposable. Don't overspend if you don't have to!) and I haven't had a problem. Pads are a drivers choice,
Stainless Steel lines made little difference. For autocross I never had any issues with brakes and as mentioned above with my roadcourse pads in the first few runs were just a warm up. Autocross is HIGHLY dependent on tires and a close second experience.
We need more information on what you want to do and your budget. It sounds like you just don't fully understand the situation fully yet. Hell, as with most things, pure experience will let you take advantage of even the stock hardware in both instances better. No sense in dumping 2K in a
braking system and you're still braking at marker #5.