I didn't realize you had said Repub side. Regardless, they are end-game/end-story quest turn in rewards.

Most of it comes from the major quest chain turn ins for the sith inquisitor towards the end of your journey. I started getting pieces at about level 45-47 and ended at 50. It was a shame I didn't choose most of it, I took the commendations. It's all Orange(Modable.) Last piece, leggings, drop from finishing your very last quest after you end your story. I hope this helps.

In Taris there is a matching MODIFIABLE armor set for the Sith Inquisitor: Assassin AdvancedClass. There are two separate choices to choose from. Renowned Templar and Renowned Assassin. Templar is red and silver aesthetically and is for Darkness/Tanking spec'd SI's. Assassin is bluish-purple aesthetically and is is for Deception and Madness spec'd SI's. The set consists of: Head slot, Chest slot, Legs slot, Hands slot, Feet slot, Bracers and Waist slot. I have the entire set EXCEPT for the Legs and Head slots. My entire reason for writing this post is to ask any Sith Assassins that might have fully played through Taris WHERE CAN I FIND THE LEGS for this set? I assume that every class/spec combo has a matching modable armor set to be found at the same points on taris as the sith assassin, so if anyone has come across the matching orange quality modifiable leggings or head piece please post a reply with the name of the quest and if its heroic or not. I have also completed the bonus series for Taris and it was not a reward for that either. I hope someone has come across this. Thanks in advance.