I guess I should have pointed that out. I do sort of get the impression that Leiffi is from across the pond, so I wasn't expecting him to be right on top of things going on here, though I may be wrong about that.
I agree with Weston, though while somewhat dated, 5 or so years ago one of the best superfarms in the country made 100+ dyno runs tuning. Pretty sure it was a riverside engine. They gained a total of 8hp tuning, and the stock 619 intake made the most power.
Same goes for what was previously (until the end of last year) the top pro stock semi in Ohio, who also spanked many of 4 charger semi's at bowling green for several years. After dozens of dyno runs and half a dozen manifolds that cost stupid amounts of money, the stock KTA manifold is making the most power. I haven't seen what Fink put on the latest top dog in the class.