I'm not looking for an argument, guys. Normally, I run the 93, but I have a 3,000 mi. trip, pulling 5,600 lbs. At 65 mph., she gets 7+ mpg. Call it 8, and that's 375 gal @ $0.40 per = $150.
Since there's zero appreciable difference in MPG, and it will not hurt the mechanics, I'll run 87 on...