What is your intention for the bike, it really depends on what you will be using it for. Are you interested in rideability improvements, looks, both? Will you be cruising around town, riding canyons, going to track days? Comfort, power, handling, cosmetics, etc., lots of areas can be improved, all it takes is money. There is no wrong answer, we are all riding for different reasons and motivations, but knowing what you will be doing with the bike, people can make their recommendations based on what you want out of it.