changing order to 2003 isn't too hard, and a good first step in taming the gp4 beast.
it involves the carshapes files (named like car_minardi_car1_lod_1.gp4).
back up your cars.wad first.
then download EasyWad by Zaz from this site.
copy your cars wad to another place (temp/)
after installing EasyWad you should be able to right click on the wad and 'Decompress it to a folder'.
with the cars they are named sfter 2001 order.
so team 1 is called car_ferrari_carX_lod_Y.gp4 etc.
so if you want minardi in slot one, just rename all the car_minardi_carX_lod_Y.gp4 files to car_ferrari_carX_lod_Y.gp4.
for 2003 order i'd make 8 new folders, (temp/williams, temp/arrows etc) and copy one teams files into each.
ferrari, jordan renault/benetton remain unchanged, so you don't need to do anything with them.
rename he bar files to sauber and vice versa.
do the same swapping with mclaren and williiams
rename jaguar to arrows
rename minardi to jaguar
rename toyota to minardi
rename your 11th team to prost.
you'll also need to do the same renaming with the cp_TEAMNAME.tex files. (the cockpit textures)
copy all the files back to where you got them (temp/cars/cars),
and right click on the temo/cars folder and choose 'recompress to wad'.
maybe i've said it wrong, but try if you like
make sure you backup.
____
Tony