Not for sure.
nelson fox
You probably mean Need For Speed. Racing Games
If you mean moding NFS Most Wanted,here is my answere. Yes, you can mod it. If you have internet in your own PC, just go to "nfscars.net". You will get most of the mods for NFS Most Wanted on this website only.
Nfs underground 2
If you mean NFS Underground 2 then the answer is yes.
No, nfs run is like more 3D-ish and exciting. i would rather prefer Nfs Run.
NFS stands for Need For Speed.
NFS Carbon
I think you can do nfs over ssh somehow.
No, but mean people may use Facebook.
Nfs underground rival is like nfs most wanted
There are no cheats for nfs undercover ps2.