Want his clothes? You'll have to do the "Destroy the Dark Brotherhood" quest line rather than joining them. If you're on PC by some chance try the Immersive Armors mod.
There are clean unenchanted hooded black robes in the game you could use. Thats really all i can think of for console players.
Nazir's clothes require degrees of swag you could never hope to achieve.
You can get it... from his cold, lifeless body.
Arent his Redguard clothes the same as the Al'kir in "In My Time of Need?"
Nazir has unique red Redguard Robes so no.
you get them only if you destroy the dark brotherhood
this bothers me too, same with thieves guild armor.
Beth's not the only guilty one. Ubisoft seems to think that assassins dig uniforms as well.