Hopefully you have found enough Knowledge in the posts above to help you make an informed decision. Changing your final gearing to suit you riding style and needs is so easy on a bike that it almost doesn't make sense not to. If you're light and do a lot of highway riding, go down a tooth on the rear and save a little gas. For more street pickup, +2 or +3 in the rear will give you a wheelie monster every time you grab the throttle. That will also shorten your wheelbase a little, so going down one tooth in the front will do about the same without it being quite as wheelie prone. You shouldn't need to deviate from these unless you're running an extended swingarm and /or taking it to the strip.