I think you guys have completely missed it. I think the dyno operator is trying to tell us that the car put down 176.67whp, and then with just a slight change he was able to get 191whp. I don't speak Korean, but that's what I would say, judging by how at the end of the video he fixes the image on the 176.67whp dyno, and not on the 191whp dyno. I can't figure what the change was, but there has to be a change. That is quite significant. You can't just gain 15whp doing nothing but running it again. Generally the first run will be the lower reading, then the second will be the highest (by maybe 2-3hp at most), and then it will gradually get lower and lower due to heat buildup and not having the 60/90mph wind you would have at the top of 2nd/3rd.
It could be that he simply took out the intake filter, but left the box. It could be that he added premium instead of regular. It could be that he added an exhaust or downpipe to it.
More than likely something simple, like a slight intake change or fuel change. The dyno reading shows the power to be the same on both runs up to about 4700RPM, then the power starts to go up from the lower reading run. He gained about 10whp between 5000RPM and 6000RPM, and then nearly nothing at 6300RPM... and then it moves up gradually to 15whp gain at 6700RPM.
The video has a shot under the hood, and I'm not that familiar with what is where, but it seems like the stock intake box is in place.
Lastly, Hyundai has stated that the peak power (210hp) is reached at 6000RPM for the 2.0turbo, and that my friends, is 176.67whp. Check the specs here:
Genesis Coupe Specifications
I rest my case. I would say it read 176.67whp stock, and 191whp with a simple mod (that we don't know about yet).