Has your buddy put a camera scope down the intake valve area ot visually looked to see how much is caked up on the valves? If he has, and there is no build up I would very surprised. If he ran a catch can, low or no buildup is plausible. If you google around and also on you tube, you will see plenty on the subject in terms of eidence.Are there actual examples of carbon deposits on these engines, or is it all just theory thus far? My BIL has a 2015 F150 with the Ecoboost and he's way over 100k and has had no problems at all.