From almost worn out shitty front pads and oem rotors, I upgraded to RDA slotted rotors, bendix ultimate pads, stock lines, new fluid, brake master cylinder stopper. And It made a world of difference and it is DEFINITELY noticeable.
Did the rotors and pads first, and even then, there was a difference in stopping distance, maybe because old pads were just crap.
Then the BMC stopper made my brakes FIRM and a much better feel in braking, no more unresponsive spongy brakes.