Unlike the standard TIE/ln starfighter, the x1 had a much more robust spaceframe, with reinforced durasteel-alloy hull, providing greater protection from enemy fire and stability during strenuous maneuvers. Also, abandoning previous Imperial design policies, considerable resources were spent to make the TIE Advanced hyperspace-capable, and the fighter was even equipped with deflector shields.

Unlike the standard TIE, Vader's had larger, angular wings. The rear engine was considerably longer, and the support struts connecting the cockpit ball to the wings were much thicker than standard.

Faced with a daring attack on their seemingly unstoppable Death Star battle station by tiny Rebel starfighters, the Empire was willing to trust the technological giant to crush the smaller foe. Yet for all its power, the Death Star's ponderous turbolaser cannons could not track the swift Rebel fighters. One person saw the pride in the Death Star as misplaced -- Darth Vader, Dark Lord of the Sith. Unwilling to underestimate the Rebel threat, Vader personally commanded a hand-picked squadron of TIE fighters into battle. As the Imperial fighter craft screamed into space, Vader sat at the controls of his own customized fighter.

Vader was responsible for the death of many Rebel pilots in the assault. A well-placed shot from the Millennium Falcon's laser cannons destroyed one of Vader's wingmen. In the confusion that followed, the remaining wingman collided with Vader's ship, sending the Dark Lord spinning out of control into space."

Sources:

• www.starwars.com. Database.