Different than stock. Just like custom stereos. Custom speaker boxes (even if they are a cube) Custom paint (like to hide a scratch). Custom rims (again, non factory) Custom tints (fronts aren't tinted from the factory) Custom Exhaust (you were to cheap to buy a premade kit and saved yourself 1.98 because you didn't calculate your labor time because you feel like your time is worth nothing.) Custom Interior (cause you bought seat covers).
The letter K can be swapped with the letter C. This amplifies whatever you did to the 12th power and shuts down anyone that says you bought everything from JC whitney.