I did the following in this order: One at a time! * The Rapture Airbox mod. What a big difference it made much better response. * JD Jetting Kit. (red needle and 178 main) This is the single best mod I think you can do. It really cleaned up everywhere and it did wonders to the bottom. *Power Now. All this thing did was to help starting. Maybe a little to the bottom response. * Oversize accelerator pump cover. This did noting to the 03 I do not recommend spending the dough. Overall: Spend some time and cut your airbox, remove the backfire screen, remove the side cover vents and install the JD jetting kit. Forget about everything else. I race and trail ride the Kommunistfornia high desert. The elevation ranges from about 2000-4000' the temps when I rode where about 45-65 degrees. At the lower temps the blue needle is the ticket!!