RAH DX Athrun (2005) was off model and had a funny pose. G.E.M. series Athrun (2012) resembles Hirai's character design more, but it also has a slightly inaccurate hairstyle and is obviously meant to be looked at only from certain angles (meaning not from these ones). The head is adjustable because it's attached to the neck by a peg, but it's not about the head, it's that spine and, and.
I might try the smiling face and the Haro sometime.