So the fraudulent BoV company then. That video of the blue STI is a fake. That driver has a Tial 50mm alright. The reason it was surging was because it was adjusted for higher spring pressure because he had a GT40 setup. It's supposed to surge at low boost when it's adjusted like that, it's not opening enough at those boost levels. The rest of those clips (Synapse and "brand x") were audio dubs over the exact same clip from the Tial surging. The author found out that someone used his video unauthorized and posted the original clip on NASIOC a while back to shoot them down.
You are giving into their fabricated sales pitches, not proven fact.