Interesting video of a vw gti 2.0t turbo running regular vs premium. Running regular they dyno'd and had 236hp running premium 241 hp. Dont really thinlk you would notice 5hp. For those of you on the fence this is a strong argument for regular, I would just buy it from a good source. I have run it in my 2018 A4 for 20k and 2018 Q5 for 18 k miles. Before had a 2007 A6 3.2 with 12.5 :1 compression which ran on regular for 150k miles without issue. And that is extremely high compression ratio in that engine. Just wanted to pass some factual info....
https://www.youtube.com/watch?v=d8L-X89duEs
https://www.youtube.com/watch?v=d8L-X89duEs