[Sven7]

I heard somewhere a long time ago that every 1psi low you are, that's 1% lower MPG. So if you gained 10psi you should gain 10% mpg. Can't say if that's true, but interesting food for thought.

I'm running 5W-30 instead of 10W-30 and haven't seen any difference. It seems to only help on startup because when the engine is warm the viscosity is the same (30).

Try more aeromods. I drive pretty normally, verging on the aggressive, and while I have a higher-displacement engine than stock it still manages 18% over EPA. Something's going right (and it's probably not the oil viscosity).