I just read a bunch of stuff down this page, and I think its all nonsense. I'm talkin about these $500 freakin Whiz-Bang!! airboxes. None of you guys have dyno'ed one yet have you ?... I didn't think so...And I don't believe a word of it either till you do... The human body is a bad instrument for measuring horsepower or acceleration... I bet that what you think is an increase in low end punch is actually just the sound of the carb gulping air when you crack the throttle, and if its louder it must be faster right!.... I don't get it...You guys think Yamaha can design a great cylinder head with high flow ports, good combustion chamber design, and a good exhaust and carburetor (I know its a Keihin), but they can't design an airbox? Save your money and concentrate on improving your riding.... Then you won't feel so bad when a guy with a stock bike smokes your class.... Flame on.