A REAL tuned header is one that has the same reversion characteristics in each primary tube. Same exhaust volume, same backpressure and so on. not necessarily all the same length tubes, but they can be. Few companies actually make real tuned headers anymore. Usually, what has been adopted to mean a tuned header is one with equal length tubes, but it's not really the truth. As you can imagine, real tuned headers are very costly and only custom made. I think for a Mopar, there is only one answer. Which one fits best. Everything else that you may get with the one that fits good, is just icing on the cake. I think all headers will flow much better than any manifolds, so there's your performance difference right there. Few applications IMO actually NEED a real fully tuned header.