Yes Tribesman, easily 5% difference in dynos, but I don't think 5% covers the "wrong" that Gotcha is concerned about. Both the 3.8 and the supercharger are very costly upgrades; high four figures at least. The plenum and throttle body is comparatively cheap. I have looked at a lot of dynographs posted for these modifications, well the 3.8 and supercharger at least, and I don't believe these are unrepresentative graphs.
Sure, a few percent out for different dynos, but basically, that's the shape and scale of the power curves delivered. I don't believe one should expect much more from the 3.8 and the SC; it's more that I'm a bit shocked at the improvement from the plenum (the throttlebody is probably a very small part of this gain).