The Transcencia Star Base gains increased armor plating, additional shield production arrays, and more damage repair systems greatly enhance the starbase's survivability.
In general this is used heavily if you are in the suicide spot. After getting Enduring Devoution it is wise to put one point into Enhanced Preservation. Other uses for this upgrade is after you research the intent for what you want your starbase to be, such as a Meteoroid Control Starbase with Punitive Measures. Its not a bad idea to put the last few points into Enhanced Preservation. Meteoroid Control mixed with fully upgraded Enhanced Preservation improves the effective amounts of times you can use Meteor Storm upon your enemies.