Man, that's gotta be a buzzy little box at 70mph. And it's built like a
toaster, if you can stand to do it slowing down has got to be of some benefit to your mileage.
The addition of the taller OD for fifth on top of your taller final drive looks like one hell of a swap.
Heh. I just realized that's a variation of the engine in the first-gen Prius. Imagine a Prius drivetrain in your XBox, that'd be fun.