hey bud ,Quite right who wouldnt be happy on 2 wheels!as for the question... 4 into 1 exhaust is ussaly good for a couple horses, also with that you need a jet kit.to help smooth the fueling.but even with the mods your current kaw wont have the snot your Katana did. the upside is the kaw is lighter and much more nimble. lotsa fun on twisty back roads. so you sacrifice some top end for rideability. no biggie. right ? nice chating ...write some more!