Instructions: First you need WinRar, if you don't have it Google it.
Download the file and extract everything from the .rar file to your Desktop.
Now cut/copy the music folder to "C:>...>Cross Racing Championship 2005" and that's it!
NOTE: the "..." isn't a folder it's the directory to where you installed CRC. It can be "Program Files>Invictus>Cross Racing Championship 2005" or just "CRC>Cross Racing Championship 2005".
Now just launch the game and you should hear the new music! If you're having problems, PM me and I'll help you!