I have expanded the rpm range to lean out. I now have leaned out from 1800 to 2600 and up to 40% load. This will cover pretty much all cruise conditions. Switching between the stock tune and the modified tune while on level ground steady throttle and speed (60mph) I saw instant milage change by 7 mpg with no change in the feel of the car.
I have an ecu that allows instant switching between tunes.
Today I drove the 485 loop 69 miles (I know it too short to get am accurate read) my trip meter clicked off 29mpg when I pulled into my drive. That's 9 mpg better than EPA rating. It's a good result for a car that will not be visually altered for milage.
Oh btw the odo rolled over to 256,000 miles on that trip this is the original engine. It's never been apart as far as the records show.