Some of you are out of touch:
#1. It's IMPOSSIBLE to lug a modern automatic tranny, engine combo. The engine will upshift every time. "You" may "think" it's lugging, but's according to the engineers that set up the software controls, it's not.
#2. Ever hear of variable displacement oil pumps?
Link#3. The more air you put into a diesel the cooler the EGT. Exactly opposite of a gas engine. There is a reason my buddy puts 140+ LBS of boost in his engine. Even at that the aluminum pistons would melt. He went to a steel piston and all of the problems went away.
#4. The more HP you have, the less gear you need.