Not being familiar with the Honda's (as much as some) I can still say that if you add a slip-on exhaust you MIGHT be ok doing nothing. However, it wouldn't hurt to add a fuel controler (or rejetting) to ensure you don't run lean. Chances are though, if you just add a slip-on you are not going to lean it out. HOWEVER, consider this. If you are adding an exhaust for performance, you are trying to let the machine breathe better. Adding an exhaust lets the machine "exhale" better, but does nothing for the "inhale" therefore defeating the purpose IMO. I would seriously consider opening the airbox in someway if you are going to add an exhaust but in doing so, you will want to add the fuel controler or jets to ensure you don't burn up the engine with a lean envoirnment. Besides, running lean also robs you of the almighty horsepower. (Too rich will foul your plugs and bogg you down.)
Somebody bash me if I'm out of line. nobash
Somebody bash me if I'm out of line. nobash