Originally Posted by Adamantium Man
This would be my cue to mention that I still think that Tony has an upgraded version of Extremis by the end of IM 3.
That was JARVIS controlling all of the armors at Tony's command in the finale. Tony was still using the implants under his skin to summon the Mark 42 armor, however. He never had himself infected with the Extremis virus/drug, which I think was a wise decision on the writers' part. Tony needs to remain "a man in a can" to stay true to who he is at core. Having the arc reactor removed from his chest was in line with his heart transplant in the comics.