I don't know about the undertail but there is a thread around here about the integrated tail light. I don't think it fits the 08 because of a minor difference in the back of the light. You could prob find it searching for it.
I already know about the thread. The reason I ask is because if the undertail fits, that would take care of the 06-07 integrated taillight not fitting. You wouldnt even notice the V not fitting correctly.