The problem with moving files between folders (or drives) is when external files (like external styles or Multipads) are used. If all referenced styles, voices and Multipads are internal, which do not require a filename to be stored in the registration record, then you can move them around to your heart's content without any issues.
Yamaha is very consistent keeping the numerical identifiers (used in the registrations for styles, Multipads and voices) consistent across all the keyboards. So, when using registrations from older keyboards, it is very probable that the used styles, Multipads and Voices will be available (not always, but most of the time). There are lists comparing what is available on different keyboards to make it easy to determine if a given resource is available or not.
To reiterate: issues only arise when using external styles (or Multipads or Voices).
Regards!