The Imperial Courier is the quintessential Imperial ship. It epitomises elegance of form while packing a good punch. Officially the class is used to provide transport for officials that don’t warrant the use of a Cutter or Interdictor. However it’s flexibility means that it fills many roles within the Imperial Navy and prominent citizens.
Source: The Game Website.
The Imperial Courier is a fast multipurpose ship just barely larger than the Sidewinder. It is the third-lightest-hulled playable ship (after the Sidewinder and Hauler) thus far but its upgrades are heavier.
The Imperial Courier is armed and very well shielded for its small size, making it a great and evasive fighter in combat. In terms of agility it ranks somewhere close to the Viper MkIII. While it has a good pitch rotation speed, its slightly weaker vertical-lateral thrusters cause the Courier to drift more than the Viper. Even though the Courier has the same top boost speed as Viper, due to its low hull mass relative to modules, it is slightly slower and can't boost as often as the Viper, dropping down from the top speed faster.
The Imperial Courier's shields are much better than the Viper MkIII's and Cobra MkIII's, being almost on par with those on a Vulture. Unlike the Vulture, the Imperial Courier does not have as severe of power management issues, and is thus better able to equip shield boosters and Shield Cell Banks.
Source: Alpha Orbital information site.