Don't fix it if it ain't Broke!!!!!!
That being said, if you must do something, changing to a cam gear is a good idea, takes care of any cam chain stretch issues. Doing some simple mods like breather kit, pipes and performace module will not only help with performace but reliablity and streetability. Allowing the motor to breathe better increases HP and improves gas mileage.
Something less invasive that can be done could be a tricked out paint job. It all depends on how you want to spend your money. Personnally, I like performance...
Good luck with your choices!!!!! Ride Safe!!!!