Altough not made during a specific time frame these guns include parts from more then one generation and fit best in their own category. They all come with a Generation 2 body and Generation 3 frame and internals.
The Empire Intimidator includes several unique parts. Changes included redesigned trigger frame that is only found on the Empire and Dragon 2.5, an all delrin Empire poppet that fits a Gen 2 ramsleeve, and a larger front block that fits bodies that aren't tapped for Gen 3 front blocks.
The Dragon 2.5 is an update of the popular Gen 2 Dragon. It includes an Empire frame (or in some cases a 2k5 frame) with updated electroncis, and Gen 3 front block, and Gen 3 internals (?).
The 2k5 incorporates a Gen 2 body, front block, and internals with an updated frame and electronics.
Gen 3 Intimidators, a refinment of the Empire, were released in late 2003. The have a shorter body and bolt, redesigned trigger frame with an LCD screen in the grip area, smaller eye covers, delrin poppet, new ram sleeve and smaller LPR. The bumper was removed from the ram and placed on they ram cap instead. They also came with Frenzy boards, a new wiring harness, and faster Humphrey's solenoid.
Atomix (A Bomb)
The Ripper 1.25 is often mislabled as the Ripper 1.5.
Miami Rage D2 team Alias
The largest changes are a smaller body, shorter bolt, new trigger frame, and new internals that feature a pressure balanced poppet. This allows the marker to use a much lower LPR pressure which helps reduce kick.
I hope this is helpful. Again, if you find any errors or have any suggestions let me know.