AFAIK the difference is only in the final drive ratio. North America was supposed to get taller final drive, same as rest of the world, but MazdaNA said it wasn't quick enough off the line for NA tastes. That's supposedly why the car had a delayed launch in NA, to change the final drive ratio.Just wondering if any of the non US spec'd MS6's had a different setup from ours. Then if we ever had the tranny open we could mix and match parts! I might change 6th to get a little better mileage if it was an option. Mostly I'm just curious.