For a specific car the stopping distance depends mostly on the tyre. Wheel alignment, tyre pressure are factors. Also the further you deviate from the standard set up the harder it is for the ABS to function. The only way you would stand a chance of out stopping an ABS system would require 4 brake pedals and 4 feet to operate it. As the ABS modulates the brake pressure to each wheel individualy in a time cycle way shorter than human reaction times. So alternative pads , race fluid, braided lines and additional cooling air ducting is almost certainly all you need. Unless you are running in a race that does not allow ABS or you wish to change for cosmetic reasons. Contrary to popular belief as has been described above bigger brakes do not stop faster they just lock earlier.

If they're really that loud, then I'd pass. But depending on who you talk to though, some say it really isn't that loud...?

But back to the original question. I thought this was a good read StopTech : Balanced Brake Upgrades