You do realize that its not just the exhaust gasses that make a turbo spool right? The first video I heard no turbo spooling and I didnt hear any blow off unless he had a recirculating valve. All I saw was a 2 step being used. The second video I didnt hear the turbo spool up like you would want it to. I didnt hear a thing until he got off the gas and that wasnt a spooled turbo lol I can make my turbo do that just by revving it up.
This is my old old old setup after I turned the timing way down look I dont need a 2 step to get mine to spool. The whole point of anti lag is it lowers timing and adjusts fuel.
Video - Isuzu Impulse rs revving