You're using an outdated image. Kongu now has armor on the front of his arms, instead of the back, while the ammo has also changed position.
Here is my opinion on Kongu:
The thing on the back of his head is cool. The ammo on the arms, I don't like, if it has to be there it shouldn't be sticking out like that, it looks weird. Also, the silver thing should have been on the front. I mean, why does he need extra armor protecting his back? Shouldn't he be a little more concerned about the front?
Grey is fine, but a Toa of Air that short is not. Kongu is one of my least favorite Toa Mahri, but I like his mask. It looks like Defilak's Kualsi mixed with a green Ruru, but better.