It makes 158hp but, an additional 30 at top end. (188 claimed). Saw this on "Twist of the Throttle: Yamaha" last night. They said the new R1's are built with a vacuum system that inducts cold air at a high right, exurting all the hot air, building a max horsepower gain of 30.
Sounded like crap, but it was from Yamaha's lead designer, and being that it competes with 180 HP bikes as it is, it'd make sense.