Stop in for a cup of coffee

Tooljunkie said
Yup, it was nice! I ran premium gas for the first time. It almost seems exhaust tone was quieter.

Thanks for posting those photos.

As far as the fuel making a different sound - could be a different burn.
When I was looking up distillation curves, sometims there were big differences, sometimes not. The octane number doesn't clue us in to that either.