+1 on 93 octane especially in summer. My rule of thumb is 93 degrees outside needs 93 octane in the tank, or the car gets sluggish. When it’s not hot I can get away with 89 though. These observations are from over 250,000 miles on a 2011 Cruze and 56,000 on a 2019.Over at the cruzetalk forums theres several threads that lead me to use 93. People mentioning timing retarding, less pep etc. Also the newer ones had holes being burnt into pistons and 93 seemed to prevent that from my reading. Knock on wood but I havent had a single issue with my cruze so I'm going to keep on doing what im doing.