On the bigger set-ups Duy, yes i have seen a few back to back dyno results but they wernt online, alot of the IPS back to backs were done compared to smallish itbs hanging out the front of bonnets with dyno fan on, no airbox ect, and most of them were TWM's which are the worst of them, but the cheapest so thats why they are used.

Its abit like now everyone in the K world is singing and posting the praises of the new kinsler itbs, and saying how fantasic they are and how they got 20 more horse power from there 50-54 jenvey/twm itbs against there 62mm kinslers, its not rocket science there top end is looking the goods.

The proof is in the pudding in Motorsport, itb's are fitted to everything at the extreme of N/A performance, alot of people just wouldnt have a clue on correct sizing both in diameter, length, and trumpet used, addressing its feed/intake also as discussed here, something most people that fit them think isnt required to get the most of them, hence there results against such products.