Run what the owners manual says. Anything more just wastes gas. I've heard it takes 2 or 3 tanks for the cars computer to figure out what you are using. Computers shouldn't have to think!! ROLL TIDE!!!!!
Mine runs good on 87, better on 89, and the best on 92, at least in regards to power, but it still has good power whatever I run. I usually switch depending on what the price is or what I'm going to do I.E. long, easy trip, 87 is fine, want more umpf, 92. I've also had the best luck running Chevron.
The manual for my 05 Dodge Ram 1500QC Hemi calls for ONLY 87, they warn against using 91/92 octane. I just picked up our 05 Magnum today and noticed the 89 requirement. Be curious to know the tuning differences between the two engines.