Increasing plug gap makes a pretty significant difference, as does increasing tire pressure. Those are very good numbers on an automatic though. Nice work!I was using 89 oct. and before the mods I was at an avg of 25-30. I never saw over 30 mpg and I drive 83 miles round trip to work everyday. I have left one of my trip trackers on my DIC alone and have never reset it I have 26,000 miles on my car now and the lifetime avg is 29.1 so going from around mid to high 20's to 41 mpg after doing the plugs and such is HUGE for me!!