If that's the case, shouldn't the HP numbers have changed for all other cars too? Why did only the R change its measurement?
Here is the best explanation I could find.
Volkswagen used to measure horsepower using "Metric Horsepower". They have since switched to measuring horsepower using "Mechanical Horsepower". What does this mean?
2018 year, VW rated the R at 292 "Metric Horsepower"
2019 year, VW rates the R at 288 "Mechanical Horsepower" or "Imperial Horsepower"
The power has not gone down, the way it is measured has changed.
Just to be very clear, 292 "Metric Horsepower" = 288.004 "Mechanical Horsepower"
So like I said, nothing has changed. It's simply the method of which VW measures the power output of the car. To your specific question about other models, I'm not up to speed on the HP ratings of other models or how they have changed year over year, but I do know they continue to ADD more power in certain models like the GTI. Just because the measurement changes doesn't mean you can't add more overall HP to a vehicle. Again, I'm not sure if HP changed in other VW models from 2018 to 2019.