dont know much about the differences except the 03 motor is supposed to be a little better than the rest of the rc valved cr's 02,04
i absolutely love my 03........ when i say jump it says how high. feels like a feather in the air . i went from a C rider straight to a B rider the day i got it!!! the ergos, power, brakes, handling, and STOCK suspension with the clickers still @ 2 clicks from stock are all confidence inspiring. maybe too much confidence..................hey why is that landing ramp way :yikes: back there.
anyway get the jetting sorted out and you will have a great bike