WDTV SMP metadata and existing metadata (XBMC)

My content is already orgnaized in a way compatible with XBMC, including metadata.  I’m a little afraid of letting the WDTV SMP go to town for metadata.  Do I have anything to be concerned about or will it just put additional metadata files in the folders?

Thanks!

It just adds its own data.  Nothing to worry about.  Your NFO files will remain untouched.