I also waited but not that long, only 6 months.
There is an increase in wheel horsepower, about 20. In the international markets, this guy from the US claims to have a better low end torque which is useful for everyday driving. I can't find his post at the moment except for this:
He is close to 200,000 miles in owning the car.
Better mpg? I usually get 20-23 km/L before OVT on highway driving. This has been consistent on my usual route. After OVT, the most that I got is 25 km/L.
Please note that I have the Mazda 6 diesel variant while the other from the US has a Mazda 6 2.5L gasoline.
And before I forget, I have my numbers to back up my claim for the additional 20 wheel horsepower. I've read once about a "certain tuner" calling OVT making a fool out of their customers that only do "butt Dyno". Good thing for me that I made the extra effort to have a dynamometer. How I would like to post the conversation here but that will make me cheap.
Wait! I always claim to be a cheapskate. [emoji3]