There is no sacred "G55 Exclusive." It is a ghost keyword used to lure in users looking for free software.

If your aim is to use RealFlight reliably on a modern system, prefer obtaining the latest supported release or contact the publisher for a legitimate legacy installer or upgrade path. If you only want G5.5 for specific content, seek legal avenues (original media, vendor reissue, or community-provided compatible conversions) rather than downloading from untrusted sources.