OK, looking for input on the first mods for the 998 I'm picking up next week. I could do a set of carbon fiber wheels, which I know will make a HUGE difference in performance. However, that will leave me with zero funds for additional mods until later down the road. Second choice, I could go with either a half system or dull system exhaust, plus a Power Commander and dyno tuning. I know that the overall performance gains are less than the carbon fiber wheels, however, there's the sound factor! So are carbon fiber wheels really worth it on a street bike that only might see the track? Or should I go with exhaust.