DATtool can be used to extract and repack the DAT files (like audio.dat) from Richard Burns Rally.
DATtool is a command-line application, so it can be easily used to do automated installations. It also supports Windows Explorer “drag and drop” use.
To use from Windows Explorer, just drag a DAT file over the DATtool.exe icon to extract it. ‘audio.dat’ would be extracted to a directory named ‘audio’. To repack the directory to a DAT file, just drag the directory icon over the DATtool.exe icon.
To extract archives from the command line, use ‘dattool -e file.dat directory’. To create a DAT file, use ‘dattool -c directory file.dat’.
Note that DATtool overwrites all files without asking, so make sure you know what you are doing and always make backups of the original game files when doing modifications.