I noticed that too. He has a really heavy differential in there that's Overkill, he has a overdrive transmission which eats up power but not only that..it has a numerically lower first gear 2.45? The 904/998/999 had lower 1st up to 2.71 or something right...
... And then he probably had a cam thrown in that sounded like it would be a power maker in the description...but quite possibly he has stock replace or a non blueprinted compression ratio..coupled with stock'ish timing, possibly not degree'd and taller tire offsetting the rear 3.73 .
Just what I first think of from the opening post.