Do you have the 2022+ HO 2.7? I have the previous one and I never use 93 octane I don’t think it’s necessary. I use 87 and it’s great.
as for the sound, that’s the only difference I felt when driving the 5.3 and 2.7 back to back. I put a CAI on it and while it probably doesn’t do much it did make the engine sound better. Not like a V8 of course but less raspy and more growly. I like it alone for the sound.
sounds like your MPG are pretty darn good. I have a lead foot and I get crappy city gas mileage and great highway.