Actually, Brock uses a happy dyno. So don't worry about the final # but the difference afterwards. With Brock's exhaust, airbox mod, Pair Valve removal, Powercommander and a good tune will give a bump of 15 hp as a realistic boost. Typically, the Gen 1s make 153-155hp stock. He also used MR9 fuel which will give at least 5% increase in power, so that's about another 7-8hp.
The #'s are not that impressive as far as dyno #s but once on the road and able to utilize the Hayabusa's efficient ram-air the bike will move better than what the dyno #s indicate. Mine didn't really make that much power and it ran quite well at the drags.