I'm speculating this:-

Since they are playing element rider, red is fire, blue is water, green is wood (this is for chinese five element, in japan, they usually refer to wind), yellow is earth.

There will be one more style, gold, the design will turn most of the suit into gold color.

Big difference, bro, from body to design, it's fairly to say that they redesign the whole thing.

You may find a line where it's use to stick the armor together, the line is at the side of armor, just cut the line but not wholely, slowly cut it until you think you could peel if off, it's hard to explain why, once you peel it off, you'll know why you shouldn't cut off the line directly at once.
After that, you may take the armor out of the body, other than that is easy, not cutting will be needed.