I'm also thinking some forced induction - and well done. Chassis is set up well too. It digs in and goes. Someone knows what they're doing.
The guy I sold my bike to went to a 'Busa meet and met (hence the term "meet") a guy with quite-stock-appearing (so no drag-length swing-arm, etc) turbo 'Busa with a dyno sheet showing 625whp. Okay, this is getting completely nuts. 220hp bikes are fast. 300hp bikes are ridiculous. 600+hp? How can you even use it?
As to the H2 and H2R, all the reports I've read/watched about the street version say that with 220hp, it's fast, but it's the supercharged power delivery that makes it so incredible. The roll-on or corner exit capability is unlike any other bike. And I guess the chassis is way better than people thought (there was lots of poo-pooing it thanks to the weight) and it is very, very fast.
The H2R is stupid - and AWESOME. I understand it's so loud it hurts.