Technically I am not switching the two I am just providing the functionality for the new Engine as all my code is wrapped up so that you can easily replace 3rd party libraries. It is still taking some time as I am having to learn this new API, although I have noticed that the Physics engine all tend to follow the same names such as "Actors" and "DynamicRigidBody". I will hopefully have a new demo up and running before you know it, I am still trying to juggle iOS development at the same time as this project and it is taking its toll on both projects.
Keep it easy :)