LOL... they should have tested the tornado and leaf blower together!
I'm not all that surprised it gained a few ponies... I doubt it truly pressurized the intake, but instead of the engine having to pull the air in itself, it's getting a bit of assistance in over-coming the drag of the intake tract.
Still, highly unpractical for legitimate use; and 10-15HP really isn't worth the associated problems (or horrible 2-cycle noise under-hood)