damn every one has different experiences for me I own a 2014 Silverado double cab v6 2wd and ran only 89 (chevron exclusively) for almost three months I filled up 5 or 6 times a month. Now I'm filling up 4 or 5 times (rarely) a month running only 91 from Sams club or Costco.... I commute 80 to 83 miles if I drive around for lunch that's 5 days a week that's not including my little detours around the city on the weekends. when I used 89 I would fill up on the morning of my 5th day but now with 91 I'm filling up 6th day at night and on rare occasions the 7th day... I think I'm getting 70 to 80 miles more since running 91 but I didn't notice it till probably my 4th or 5th fill up I've been using 91 now for the last 7 months now and yes my car did feel a little bit more responsive I just cruise and bump my music I'm not a heavy foot driver
