I never chipped any of my vehicles as I value reliability higher than few extra HP.
Few years back, driving 7.3l F250 with light camper, I was following another Ford pulling big TT on Truckee, CA grade.
He was really "flying" for few miles, but then something changed on the truck and with big Poof of heavy smoke it start going much, much slower.
I posted question on Powerstroke Forum, but nobody could come with clear explanation.
My guess was that the guy overheated the engine, or blow the chip and coming to normal tune made whole World of difference.
Fact is that would I keep 7.3l I might not push new truck purchase, but needing dually, I bought 6l with known consequences.