Having studied the pictures of the first engine, the second engine looks a completely new design, nothing looks interchangeable. Does that mean engine design is only at its initial stages and all progress on its initial design to this point has been wasted.
Plus (to me) the engine looks longer now, although they stated it will be shorter in one of the videos due to one less turbine disc.
Why not just copy the Arriel and shrink it down for 500 HP, or is that is whats happening anyway.