When Cup2000 first came out I was a little disheartened to see that the .mips it used for blank cars in Opponent Manager were the same ones from default Cup, which meant it looked like a mess any time you made a new car/driver. I fixed that quickly by making custom replacement .mips, and I don't know why I didn't release them to the public until now.
All you have to do is drop the .mip files in your series/cup2000 folder.
All you have to do is drop the .mip files in your series/cup2000 folder.