On my Ford Power Stroke nothing, on the Dodge Cummins a lot of things.
Horton fan, electric fan
Super large oil pan
Super large tranny pan
exhuast brake
removed cat converter
removed muffler
added resonator
4 inch exhaust pipe
Air Filter, Amsoil- round one made for Chevy
air bags and air compressor
45 gallon after market fuel tank, total gallons 80.
A few more things but some were worth the cost, others not.
The electric fan is well worth it, more HP and less drag on belts since it does not run by belts.
All in all you can end up spending several grand on things if your not carefull, I know as I did.
Not about to do it to the Ford, if anything would like to add larger oil and tranny pans and another trans cooler.
Remember we pulled a 27 foot 5th wheel with this truck as well as my rig for working. All I can say is it hauled A - -.
