We use 89 for around town driving and 92/93 when we're going to do mostly hwy driving. Haven't noticed any problems when using 89, but the wife drives most of the time and wouldn't notice anything unless it was really noticeable.
2018 FWD Terrain Denali, Steel Blue Metallic, 2.0L Turbo, Sunroof.
2017 FWD Acadia Denali, Crimson Red Tri-Coat, V6
2014 FWD Buick Enclave Leather
2012 FWD Equinox 2LT V-6,