Hope this is helpful.
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Editions
The 1998 edition updated the game engine to the same version used by X-Wing vs. TIE Fighter; note the higher resolution cockpit graphics and improved 3D models
Original Floppy Disk Edition — (X-Wing engine, iMUSE MIDI music) Star Wars: X-Wing was originally released on five (5) 3.5" floppy disks and (6) 5.25" floppy disks in 1993. Its expansion packs, Imperial Pursuit and B-Wing, were also released on floppy disk the same year.
Collector's CD-ROM Edition — (TIE Fighter engine, iMUSE MIDI music). In 1994, after the release of Star Wars: TIE Fighter on 3.5" floppy disks, X-Wing was re-released along with its expansion packs, Imperial Pursuit and B-Wing, on CD-ROM. This edition includes various tweaks, bug-fixes, easier versions of certain missions, improved graphics, redesigned cut-scenes, bonus missions, and voiceovers for the mission briefings and the in-game radio messages. The in-flight engine, having been upgraded for this release, is the same as the one used in TIE Fighter, which is actually an improved version of the original X-Wing engine, modified for the initial release of TIE Fighter to support gouraud shading and other rendering enhancements. Owners of the floppy disk version could, at the time of release, send the back of their instruction manuals and money to LucasArts and receive a special "Gold Edition" of the CD-ROM version, which included the game on a golden CD-ROM and a free gift.
X-Wing Collector Series Edition — (X-Wing vs. TIE Fighter Windows 95/98 engine, Red Book audio). In 1998, X-Wing was re-released again, this time as part of the Collector Series, a compilation containing revamped versions of both X-Wing and TIE Fighter retrofitted with the 3D-accelerated X-Wing vs. TIE Fighter ("XvT") engine and tuned to run under Windows 9x. The Collector Series also includes a cut-down version of X-Wing vs. TIE Fighter called Flight School. This version of XvT was included to renew interest in the full-version of XvT, as it was selling poorly at the time."
Excerpt above taken from
http://en.wikipedia.org/wiki/Star_Wars:_X-Wing
The X-Wing Trilogy is the same as the X-Wing Collectors Edition EXCEPT it also includes X-Wing Alliance.
