[oil pan 4]

Additives are a waste of money.
Emissions are the main reason why engines have sensors and computers. A programer can increase fuel economy by several MPG but they cost hundreds upon hundreds of dollars and the payback time is likely 100,000 miles or so.
Run high way tires with snow chains for off road. Solid tire weight could destroy the suspension.
Very few mods have a pay back of less than 20,000 miles.
Going from 10w-40 or 15w-40 to 5w-30 only saves about 1% on fuel economy but wears out the valve train something like 20% faster.
The 7.3 has that funky hybrid motor oil driven injection system. Use what ever oil ford recommends, a new set of injectors for that engine will run like $5,000.