JDM vs USM SVXs

Has anyone ever noticed that acceleration and mileage figures are better for the SVX in other countries? And people say that the they use different trannies and computers between the different countries. So I was wondering, what are the exact differences between the US and foreign SVXs, and how many different versions are there? And can we put the foreign ECUs that rev to and shift at 7,100 RPMs and give high 6 sec 0-62 times in our SVXs?

I wonder if the US SVXs were just detuned to deal with our "inferior" (compared to the JDM version) trannies and emissions regulations. Oh, and what are the differences betwen the JDM trannies and ours?

And I wonder if the shutting down of the cylinder banks was also a feature left out for US SVXs, because weather i'm driving the car hard and in the city (17 MPG) or on the highway at about 60-80 MPH (19 MPG), I get basically the same mileage as you can see. Hmm..

Any thoughts?