Go watch the episode. They will prove your theory completely wrong, as all the dents they put in the system were maybe 200mm from the heads. And like said previously, even they ruled out a lot of the changes due to time of day, oil and water temp in the motor etc. etc.
Think you need to go do some more research before you keep trolling. Watch that episode then tell everyone here (especially the ones that know that sh*t) that they're wrong. Then give me all the all the calculations to explain how the cross sectional area of the pipe has been reduced. Plus all the gas flow cals that say it is going to be severely restricted.