i wanna learn how to madify a cummins and other diesels

I want to see your passenger mirror mods for holding that flag.
Does it affect MPG?
Do you fold it down to go under bridges and wires?
Special permit?

I also just noticed he asked how to "Madify" a cummins... I'm not sure how to make my cummins mad, but if I accidentally step on the foot feed a bit too hard, at a bit too low of an RPM, it sure "Madifies" the people behind me.......