I have now confirmed the rpm difference between the steel and the sport wheels. It is about 230rpm less at 100kmh with the sport wheels and tires. I have a MT.
So, I know my speedo will read slightly lower than my actual speed or it may now be more accurate as some have said the Honda speedo is very optimistic.
We put the scangauge on it and tracked the speed with a gps and another vehicle for a baseline. Then we swapped wheels a few times.
What we got was 230 rpm at 100kmh with 40psi in all wheels.
So the Sport wheels do lower the highway rpm.
The sport wheels measure nearly an inch taller. But this is not very accurate as the tires crown unloaded. I wish I would have taken a rolling unloaded measurement.