This is supposed to be his "Swat mode"
Robocop 1.0: looks like the original suit, but is turned down, because in the script, a test study with criminals make fun of it and say it looks silly. They even sarcastically reference Eddie Yang(the guy who designed Iron Man in the movies).
Robocop 2.0: Looks similar to the 1.0 variation with minor tweeks, but his armor is tinted green.
Robocop 3.0: Is still similar to the others, but his armor is now black, and has a big OCP sign on its back.
Robocop 4.0: This suit can now change colors. It has a civilian mode that makes him look like a cop in a blue uniform. When he sense danger, he'll go into "intimidation mode", and his suit changes colors to all black and looks like a SWAT uniform.
Having an "intimidation mode" makes some kind of sense, I guess, but all the other stuff just seems so unnecessary. Is there any reason we really NEED to see him in a bunch of different armors and colors over the course of the film?
What the heck does that have to do with character or story?