As Hank Pym tell us during the events of Ant-Man, that costume isn't just some cute technology like the Iron Man suit. Well, we'll hopefully get to see just how 'cute' that technology is compared to the Pym Particles when the original Avenger faces off against the newest recruit. Even before the Civil War promo art was released we knew that Scott Lang would be taking Cap's side, because of his little scrap with Falcon and the post-credits scene, and of all the guys on the other team it's Iron Man that's the most exciting prospect for him. Although this is Lang rather than Pym, which means it won't be two geniuses going at it, there's still some similarities between them, such as the suits they wear and the rather witty and sarcastic nature of both characters. Seeing what their different suits can do, and how each of them responds to that, should make for a very different (and funny) fight scene. Who will win: Ant-Man's new to the team and wants to make a good impression, and changing size will no doubt annoy Tony Stark, but what happens to ants? They get crushed. Iron Man's got this.