Well, I had QSUD 10w30 in my rogue and the engine would run MUCH better, quieter at high rpm and high speed overrun. Likely doesn't show much on dyno (as dyno does not equal real world operation at part throttle or does it simulate the cold ram air effect). Last visit, The Nissan dealer "accidentally" put in some unknown FE "dino" 5w30 and the engine wont rev past 4500 without making a all kinds of protest. So yea - if you USE your upper torque peak and run to near redline I bet this will give you a bit of a boost over "shear to water" ILSAC dino loaded with VM. Many engine will pull timing if they detect racket due to "overly sensitive" knock sensors.
Me I want the NON DEXOS 10w30 as I don't have a turbo and I (think) I want the goodies missing in Dexos to get a good TEOST. Also The oil is "lighter" at operational temps. The only dexos oil Ive run that I like over HM has been Magnatec SS - still need to thin the stuff with 5W20 to get the VVT in the correct operational range to make decent torque for low speed commuting.
What Shell means here is if you keep the ring lands and pistons clean, cyl balance will be improved and the engine will CONSISTENTLY make the power it is capable of. Ho-hum oil = gummed pistons and poor power and poor NVH.