Last time I saw 1.3% FD from Blackstone the back to back GC reading was 7.8%. Knowing Blackstone isn't wrong, they just use an outdated test, in the long run this is going to be your engine corroding away.So I did a study with a major GT-R power house. I can't name due to an NDA and they didn't want other tuning houses to see the results.
Anyways, we ran oils on 400WHP, 800WHP, 1600WHP and 2000WHP vehicles. Turbo and N/A. The difference between new oils, one in particular, Amsoil vs. RLI, was 6whp on the 400WHP N/A car. You don't even want to know the differences between valvoline and M1 vs. Amsoil/RLI were let alone on the more powerful turbo cars.
We retested the vehicles once they had put miles on them and the differences between an oil at 5,000 miles with 4% FD and one with 1%FD was over 15hp. Tests were conducted in a climate and humidity controlled environment, so no reproduction issues here.