the reason people get the busa is not just for the speed but for the power.. when you spend alot of time on a bike the last thing you want is to be going up and down through the gear box for the right gear to take the corners. with the busa you have the power that you dont even have to change gear.. even on roads with know corners the busa is happy to cruse along in top gear with the bike hardly ticking over. where as a 600 will have to do a bit of work to do anything. its not nice with a bike reving its guts out for hours
