Wrex: Family Armor

Wrex: Family Armor is gained after talking to Urdnot Wrex. You learn that he's looking for his family's ceremonial armor. It was taken by the turians after the Krogan Rebellions and now a profiteer named Tonn Actus has it.

Acquisition
Repeatedly visit Wrex on the Normandy and chat with him about his past. Eventually, he'll tell you about the armor. Alternatively this mission can be acquired by visiting the hidden structure on Tuntau. If Wrex is present on Tuntau, you will complete the mission there. If Wrex is not on the mission, you can visit him back on the Normandy after the mission's complete and give him the armor then, even if he hasn't already told you about it.

Walkthrough
Head to Tuntau. Head south and take out the mercenaries at the base. Wrex's armor is upstairs in the wall safe.

Two or three pirates outside the base, easy enough with the Mako. Once inside if you don't have the story yet, Wrex will let you know it before you proceed to the next room. The pirates in here are annoying but not difficult.

Main floor: the back room has a bunch of goodies and a "Hard Difficulty" container.

Upstairs in the back has a few items in the wall safe, plus Wrex's armor.

If you carry out this assignment before going to Virmire, Shepard will gain Wrex's trust and can use this in lieu of Charm or Intimidate to calm him down once it is revealed that Saren Arterius has found a cure for the Genophage.

Troubleshoot
If your Decryption is too low to open the safe, go back to the Normandy, then return to the base and try to open it. The skill difficulty level will change. Just in case, bring your best tech squad: Kaidan and Tali, though this deprives you of a conversation with Wrex about just how worthwhile this armor is.