Well when you look at what you'd have to do to get that engine to work in this car vs what you can do to the 320 motor, it becomes very clear that losing displacement and cylinders to add a turbo to get you back to where you were, makes little sense. And to play the back side of that, even if you built that motor for 500hp, the time and money you'd have into it, you'd have been better off going a different route anyways. Now if you asked about throwing in a previous gen straight 6 3.2L, that could make sense if only the thing would fit in our engine bay but no dice there as it's 3 inches too short.