As a result, it's not until 5,500 rpm in 4th gear that we actually see the full 263HP that's advertised. That turns out to be at 85mph.
So, Mazda is advertising a 263HP car that can not achieve that power rating legally on any public road.
If my memory is correct, there was a lawsuit in Ohio for a similar reason that resulted in lawnmowers not being rated by HP any more. The basis of the lawsuit was that the HP ratings on lawnmower engines were the "peak" power ratings of the engines, which typically occurred at 5,500~6,000 rpm. But during operation of the lawnmower, the optimal blade speed was 3,600 rpm. Therefore the manufacturers were misleading the consumers as the peak horsepower was never achieved during the intended operation of the mower. If you check the local hardware store, you'll see that almost all mowers are now advertised by their torque rating.