How do you change the number of opponents for certain circuits in career mode for NFS 4
Edit: and the names of the circuits
I don't think you can. Career mode is set by the game, and can't be changed except maybe by hacking the .exe. I'm not even sure about that, really
For the career mode:
http://nfs.onlinewelten.com/en/downloads,id1665,km_edit_3_00_w1.html
Possibly German only, though :/
And for the track names:
http://www.nfscars.net/file/view/highstakes/6653.aspx
:)