brake upgrade

[sojirovskensi]

I have almost no knowledge about the price range of getting bigger brakes.
Could anyone explain how that works?
I currently have sports package and I would like to upgrade to 6/4.. or better one with 4/2 if 6/4 setup is too expensive.
I really don't care about the caliper color but just need a better brake performance.
Should I get the kits or will it be just okay to change brake pads, rotor, brake line, etc?
What should I change and how much do they cost usually? (not like insane brake system but mediocre price...)

p.s I will be getting s/c soon and that's the reason I want better ones.