I agree with phoebeisis . . . you've got quite a good car already (I should know since I traded in a 2001 Honda Accord 2-door/4 cyl in for my HCH). Even though I never actively thought about FE when I had the Accord, my best tank was about 35MPG on a road trip. You're already doing amazing things with your Accord. How about just optimizing your Accord with LRR tires and switching to 0W-20 synthetic?