jake,
WELCOME!!!!!
Now ther are 2 4.5L q45 MOTORS on this site.
you are much braver and younger than I. I left mine in the F50 body!!!!!
My treck to better mpgs was three stepped.
1. using the mpg screen in the car, I started driving 'easier' and got the ecm & tcm to learn the mpg mode.
2. Going to a larger diameter tire 245/50/18 on the stock rims. Lowered my rpms at highway speed to around 1800rpm
3. all the other stuff: scangaugeII, and aero mods(IMPUL body kit, underbelly pans etc)
Check out the links in my signature!