I started poking around the command line looking at where files were located and stumbled apon the /empeg/lib/lang/en_UK.msgso file. Opening it up in an editor, I found the various messages located in the file in plaintext. A couple edits later, and I now have a USA Localized RioCar... Yea I know, it's nothing spectacular, but it's neat.. Attached is the replacement en_UK.msgso file.. None of the edits changed any of the word lengths, so it looks the same (just with Centre spelled Center, and Equaliser spelled Equalizer).

Steps for those who don't know:
1. log into command line
2. cd /empeg/lib/lang
3. rw
4. mv en_UK.msgso en_UK.msgso.old
5. rz
6. send the new file
7. ro
8. exit