Well, I am working on Beta right now and I chose to make a little small big change!
On the beta as you can see on the shot above, there is a breast plate, but when you transform in the combat mode, the breast plate disappear and the visual stay equals to the alpha, so to make it different I chose to create a new breastplate model for it.

When you activate the combat mode, the breastplate open and get bigger spikes exposing the inner section from the torso.