As you may know, in NFS4's car.viv-files there are a lot of files named "fedata.xxx" - these are the language files. Sometimes you may have the problem that you install an addon and it won't appear ingame.
This may happen because the author didn't put in the Fedata for your language. As example, if you have a german game, you need the "fedata.ger" in the viv.
Solving this is easy. Open the car in NFS-Wizzard, find any fedata file, copy it, rename the ending to your language and save the viv file.
These are the fedata files that are supported and what language they are for:
- fedata.bri - British
- fedata.eng - English
- fedata.fre - French
- fedata.ger - German
- fedata.ita - Italian
- fedata.spa - Spanish
- fedata.swe - Swedish
The list may be incomplete for some other language versions like australian or japanese game, but these are the ones found in the EA viv files that I know.